Urticaria (hives) - NHS Choices Urticaria (hives) Nettle-rash Treatment Introduction Urticaria – also known as hives, weals, welts or nettle rash – is a raised, itchy rash that appears on the skin. It may appear on one part of the body or be spread across large areas. The rash is usually very itchy and ranges in size from a few millimetres to the size of a hand. Although the affected area may change in appearance within 24 hours, the rash usually settles within a few days. Doctors may refer to urticaria as either: acute urticaria – if the rash clears completely within six weeks chronic urticaria – in rarer cases, where the rash persists or comes and goes for more than six weeks, often over many years A much rarer type of urticaria, known as urticaria vasculitis, can cause blood vessels inside the skin to become inflamed. In these cases, the weals last longer than 24 hours, are more painful, and can leave a bruise. When to seek medical advice Visit your GP if your symptoms don't go away within 48 hours.

You should also contact your GP if your symptoms are: severe occurring alongside other symptoms Who's affected by urticaria? Acute urticaria (also known as short-term urticaria) is a common condition, estimated to affect around one in five people at some point in their lives. Children are often affected by the condition, as well as women aged 30 to 60, and people with a history of allergies . Chronic urticaria (also known as long-term urticaria) is much less common, affecting up to five in every 1,000 people in England. What causes urticaria? Urticaria occurs when a trigger causes high levels of histamine and other chemical messengers to be released in the skin. These substances cause the blood vessels in the affected area of skin to open up (often resulting in redness or pinkness) and become leaky. This extra fluid in the tissues causes swelling and itchiness. Histamine is released for many reasons, including: Read more about the causes of urticaria . Diagnosing urticaria Your GP will usually be able to diagnose urticaria by examining the rash. They may also ask you questions to find out what triggered your symptoms.

If your GP thinks that it's caused by an allergic reaction, you may be referred to an allergy clinic for an allergy test . However, if you've had urticaria most days for more than six weeks, it's unlikely to be the result of an allergy. You may also be referred for a number of tests, including a full blood count (FBC) , to find out whether there's an underlying cause of your symptoms. Read more about diagnosing urticaria . Treating urticaria In many cases, treatment isn't needed for urticaria, because the rash often gets better within a few days. If the itchiness is causing you discomfort, antihistamines can help. Antihistamines are available over the counter at pharmacies – speak to your pharmacist for advice. A short course of steroid tablets (oral corticosteroids ) may occasionally be needed for more severe cases of urticaria. If you have persistent urticaria, you may be referred to a skin specialist (dermatologist). Treatment usually involves medication to relieve the symptoms, while identifying and avoiding potential triggers. Read about treating urticaria .

Complications of urticaria Around a quarter of people with acute urticaria and half of people with chronic urticaria also develop angioedema, which is a deeper swelling of tissues. Chronic urticaria can also be upsetting and negatively impact a person's mood and quality of life. Angioedema Angioedema is swelling in the deeper layers of a person's skin. It's often severe and is caused by a build-up of fluid. The symptoms of angioedema can affect any part of the body, but usually affect the: eyes Hives (urticaria) - Causes & treatments for nettle rash and welts Select An Article Hives, urticaria, nettle rash or welts Hives , also known as urticaria, welts or nettle rash, is an itchy, raised rash on the skin . The hives usually appear suddenly, sometimes because of an allergic reaction or being stung by a nettle. Image: © Scott Camazine / Phototake -- All rights reserved. Hives usually cause itching, but may also cause burning or stinging. They can appear anywhere on the body, including the face, lips, tongue , throat or ears .

Hives vary in size (from a pencil rubber to a dinner plate), and may join together to form larger areas known as plaques. They usually last for less than 24 hours, but in some cases they can last for several days or months before fading. What causes hives? Hives form in response to histamine causing tissues to swell. Histamine and other chemicals cause blood vessels to dilate and become leaky allowing fluid from the blood to leak out of the blood vessels causing itchiness and swelling. Allergic reactions, chemicals in foods, insect stings, sunlight exposure or medicines can all cause histamine release. Sometimes it's impossible to find out exactly why hives have formed. There are several different types of hives including: Acute urticaria: Hives or swelling lasting less than six weeks. The most common causes are foods, medicines, latex or infections. Insect bites and internal disease may also be responsible. The most common foods that cause hives are nuts , chocolate , fish, tomatoes, eggs, fresh berries, soya, wheat and milk. Fresh foods cause hives more often than cooked foods. Certain food additives and preservatives may also be to blame.

Medicines that can cause hives include aspirin and other non-steroidal anti-inflammatory medications such as ibuprofen, some high blood pressure medications and some painkillers such as codeine. Chronic urticaria: Hives or swelling lasting more than six weeks. The cause of this type of hives is usually more difficult to identify than those causing acute urticaria. The causes can be similar to those of acute urticaria but can also include autoimmunity, chronic infections, hormonal disorders and malignancy. Physical urticaria: Hives caused by direct physical stimulation of the skin - for example cold, heat, sun exposure , vibration, pressure, sweating and exercise. The hives usually occur directly where the skin was stimulated and rarely appear anywhere else. Most of the hives appear within one hour after exposure. Dermatographism: Hives that form after firmly stroking or scratching the skin. These hives can also occur along with other forms of urticaria. How are hives diagnosed? Your GP will need to ask you various questions in an attempt to find the possible cause of hives.

Since there are no specific tests for hives, testing will depend on your medical history and a thorough examination by your GP , allergy specialist, immunologist or dermatologist. Skin tests may be performed to determine the substance that you are allergic to. Routine blood tests are done to determine if a system-wide illness is present. Hives: MedlinePlus Medical Encyclopedia Swelling of the surface of the skin into red- or skin-colored welts (called wheals) with clearly defined edges. Wheals may get bigger, spread, and join together to form larger areas of flat, raised skin. Wheals can also change shape, disappear, and reappear within minutes or hours.You know you have hives when you press the center of a wheal, it turns white. This is called blanching. Dermatographism is a type of hives. It is caused by pressure on the skin and results in immediate hives. Exams and Tests Your health care provider can tell if you have hives by looking at your skin. If you have a history of an allergy, the diagnosis is even clearer.

Sometimes, a skin biopsy or blood tests are done to confirm that you had an allergic reaction, and to test for the substance that caused the allergic response. Treatment Treatment may not be needed if the hives are mild. They may disappear on their own. To reduce itching and swelling: Do not take hot baths or showers. Do not wear tight-fitting clothing, which can irritate the area. Your provider may suggest that you take an antihistamine such as diphenhydramine (Benadryl). Follow your provider's instructions or the package instructions about how to take the medicine. If your reaction is severe, especially if the swelling involves your throat, you may need an emergency shot of epinephrine (adrenaline) or steroids. Hives in the throat can block your airway, making it difficult to breathe. Outlook (Prognosis) Hives may be uncomfortable, but they are usually harmless and disappear on their own. In most cases, the exact cause of hives cannot be identified. When the condition lasts longer than 6 weeks, it is called chronic hives. Often, no cause can be found.

Possible Complications Anaphylaxis (a life-threatening, whole-body allergic reaction that causes breathing difficulty) Swelling in the throat can lead to life-threatening airway blockage When to Contact a Medical Professional Call 911 or your local emergency number if you have: Fainting Hives | definition of hives by Medical dictionary Hives | definition of hives by Medical dictionary Hives is an allergic skin reaction causing localized redness, swelling, and itching . Description Hives is a reaction of the body's immune system that causes areas of the skin to swell, itch, and become reddened (wheals). When the reaction is limited to small areas of the skin, it is called "urticaria." Involvement of larger areas, such as whole sections of a limb, is called "angioedema." Causes and symptoms Causes Hives is an allergic reaction. The body's immune system is normally responsible for protection from foreign invaders. When it becomes sensitized to normally harmless substances, the resulting reaction is called an allergy. An attack of hives is set off when such a substance, called an allergen, is ingested, inhaled, or otherwise contacted.

It interacts with immune cells called mast cells, which reside in the skin, airways, and digestive system. When mast cells encounter an allergen, they release histamine and other chemicals, both locally and into the bloodstream. These chemicals cause blood vessels to become more porous, allowing fluid to accumulate in tissue and leading to the swollen and reddish appearance of hives. Some of the chemicals released sensitize pain nerve endings, causing the affected area to become itchy and sensitive. A wide variety of substances may cause hives in sensitive people, including foods, drugs, and insect bites or stings. Common culprits include: nuts, especially peanuts, walnuts, and Brazil nuts fish, mollusks, and shellfish bee, wasp, and hornet stings bites of mosquitoes, fleas, and scabies Symptoms Urticaria is characterized by redness, swelling, and itching of small areas of the skin. These patches usually grow and recede in less than a day, but may be replaced by hives in other locations. Angioedema is characterized by more diffuse swelling. Swelling of the airways may cause wheezing and respiratory distress. In severe cases, airway obstruction may occur.

Diagnosis Hives are easily diagnosed by visual inspection. The cause of hives is usually apparent, but may require a careful medical history in some cases. Treatment Mild cases of hives are treated with antihistamines , such as diphenhydramine (Benadryl) or desloratadine (Clarinex). Clarinex is non-sedating, meaning it will not make patients drowsy. More severe cases may require oral corticosteroids , such as prednisone. Topical corticosteroids are not effective. Airway swelling may require emergency injection of epinephrine (adrenaline). Alternative treatment An alternative practitioner will try to determine what allergic substance is causing the reaction and help the patient eliminate or minimize its effects. To deal with the symptoms of hives, an oatmeal bath may help to relieve itching. Chickweed (Stellaria media), applied as a poultice (crushed or chopped herbs applied directly to the skin) or added to bath water, may also help relieve itching. Several homeopathic remedies, including Urtica urens and Apis (Apis mellifica), may help relieve the itch, redness, or swelling associated with hives.

Prognosis Most cases of hives clear up within one to seven days without treatment, providing the cause (allergen) is found and avoided. Prevention Preventing hives depends on avoiding the allergen causing them. Analysis of new items in the diet or new drugs taken may reveal the likely source of the reaction. Chronic hives may be aggravated by stress , caffeine, alcohol, or tobacco; avoiding these may reduce the frequency of reactions. Key terms Allergen — A substance capable of producing an immediate type of hypersensitivity, or allergy. Wheal — A smooth, slightly elevated area on the body surface, which is redder or paler than the surrounding skin. Resources n See urticaria. Patient discussion about hives Q. What caused my hives? I woke up this morning and saw that all my back and chest are covered in hives. How did this suddenly appear? What caused it? A. Urticaria (hives) is generally an allergic reaction, or an immune response to food or some other allergen, but can also appear for other reasons, notably emotional stress. Q. I was diagnosed with chronic urticaria. What is the reason for this condition?

I was diagnosed with chronic urticaria last week after more than two months of urticaria (I have more than twenty 1 dollar coin area no my trunk that are red swollen and itchy). when I was younger I had a similar reaction too a bee sting and I was treated with an adrenalin shoot. Since that one time I never suffered from this kind of symptoms till two months ago. What can be the reason for this condition? A. As was said before chronic urticaria is a symptom of many problems. I once took NSAIDs for knee pain and I started to itch myself. It took my doctor 3 weeks to understand that I was allergic to this specific drug. I also know that tomatoes can cause me an allergic reaction. Try to think is there anything new in your life? Tell it to the GP maybe he will be able to tell you if this is the reason for your symptoms. Q. hpv Can i get pregnant A. You can get pregnant you just need to tell your doctor whats going on so he can keep an eye on the issue. What are hives? What is urticaria? What causes hives? - Medical News Today What are hives? What is urticaria? What causes hives?

Written by Christian Nordqvist 4 172 38 Hives are also known as urticaria, welts, wheals, or nettle rash. It is a red, raised, itchy skin rash that is sometimes triggered by something that produces an allergic reaction - an allergen. When there is an allergic reaction the body releases a protein called histamine. When histamine is released our capillaries (tiny blood vessels) leak fluid. The fluid accumulates in the skin and causes a rash. Urticaria can be triggered by: Certain foods. Insect bites and stings. Contact with an irritant, such as nettles, chemicals or latex. Certain medications - such as NSAIDs (nonsteroidal anti-inflammatory drugs), used to treat pain, ACE inhibitors, used to treat hypertension ( high blood pressure ). Extremes of temperatures. Sunlight. Water on the skin. Experts say that in about half of all cases of urticaria the cause is never found. According to the National Health Service (NHS), UK, about 1 in every 6 people will suffer from urticaria at some time in their life. Children and women are more commonly affected than adult men.

Urticaria is not contagious - you cannot pass it on to another person. Acute urticaria or Acute hives When symptoms last less than 6 weeks it is called acute urticaria. This is by far the most common type. 25% of people with acute urticaria also have angioedema - swelling in the deeper layers of skin. Chronic urticaria or Chronic hives If symptoms of urticaria continue for more than six weeks it is called chronic urticaria. Dermatologists say that about 1 in every 1,000 people suffers from chronic urticaria. Experts are not completely sure what the causes of chronic urticaria are. However, most agree that it is closely linked with our immune system. In some cases, chronic hives may be related to an underlying autoimmune disorder, such as thyroid disease or lupus . 50% of people with chronic urticaria also have angioedema. Angioedema is similar to urticaria, but occurs deeper inside the skin. The swelling causes a burning sensation and typically occurs on the face and neck, fingers, toes, and in the genitals of males.

What are the symptoms of urticaria (hives)? Swellings, known as wheals, appear on the skin as a rash. They are usually pink or red and have an oval or round shape, and range from a few millimeters in diameter to a several inches. They can be extremely itchy. The wheals may be surrounded by a red flare. The wheals usually occur in batches, and frequently appear on the face or the extremities (arms, hands, fingers, legs, feet, and toes). In most cases a welt will disappear after a few hours, but me be replaced by new ones. They can appear on just one part of the body, or several parts. In the majority of cases symptoms are present for no more than 8 to 12 hours, and rarely continue for more than 24 hours. However, with some patients the problems may continue for quite a few days, and even several months. Anaphylaxis Anaphylaxis is a severe allergic reaction. The patient can have serious breathing difficulties, and can even lose consciousness and die if not treated quickly. The allergic reaction may involve the whole body. Anaphylaxis is a medical emergency.

If somebody has urticaria it is important to be alert for further symptoms which could indicate an anaphylaxis reaction. Anybody who experiences the symptoms listed below should call the emergency services immediately: Nausea and vomiting. An unexpectedly abrupt feeling of intense anxiety . What are the causes of urticaria (hives)? Experts say that urticaria occurs when the body releases histamine and other chemicals from under the surface of the skin. The histamine and chemicals cause inflammation and fluid to accumulate under the skin, causing wheals. In about 50% of all acute urticaria cases the trigger is unknown. The following are examples of some known triggers: Medications - including NSAIDs, such as aspirin and antibiotics . Foods - several different types of foods have been known to trigger urticaria. The most common ones are nuts, chocolate, some citrus fruits, shellfish, food additives, eggs, and wheat products. Some chemicals. Chronic illness - such as thyroid disease or lupus. Chronic urticaria (long term urticaria), on the other hand, is hardly ever caused by these triggers.

Chronic urticaria generally starts as an autoimmune response in which certain cells (mast cells) cause the release of histamine and various chemicals to be released under the skin, causing tiny blood vessels to leak, which results in swelling and wheals. Experts do not know why this happens. How is urticaria diagnosed? Acute urticaria diagnosis A GP (general practitioner, primary care physician) can easily diagnose acute urticaria by examining the rash on the skin. The doctor will attempt to find out what the trigger was, as this may help the patient prevent recurrences. Typically, the doctor will ask the patient the following questions: When the episode began. Where the episode began. Whether the patient lives or works in a place where potential triggers may exist, such as latex gloves, chemicals, or animals. What medications the patient has been taking, including herbal supplements. The patient's medical history. Whether the patient had been bitten by an insect. Whether any close relatives also have/had urticaria. In half of all cases the doctor and patient will never find out what the trigger was. However, most cases will resolve themselves within a few days and never recur.

If a doctor believes there may be a trigger which is causing an allergic reaction the patient may be referred to an allergy clinic (UK). Allergy clinics test the patient's blood and skin to find out whether there is an allergy to specific substances, such as chemicals, dust mites, or some food. Chronic urticaria diagnosis If the urticaria continues for more than six weeks the likelihood of there being some external trigger is extremely small; which is why allergy tests are not recommended. Nevertheless, the GP will be interested in factors which may exacerbate the existing urticaria, such as alcohol, caffeine intake, mental health (stress), etc. If there are any underlying causes for the chronic urticaria the doctor may order the following tests: A blood test to find out whether the patient is suffering from anemia . A stool sample to check for parasites. ESR (erythrocyte sedimentation rate) test - this can identify problems with the patient's immune system. Thyroid function test - this identifies either hyperthyroidism (overactive thyroid) or hypothyroidism (underactive thyroid). Liver function tests - these can identify whether the patient has any liver problems. What is the treatment for urticaria?

Allergic skin disorders, such as urticaria and atopic dermatitis, can cause much discomfort, have an impact on quality of life, and can sometimes cause serious complications. Like other allergic conditions, these disorders can often be effectively treated , according to the American College of Allergy, Asthma and Immunology. Acute urticaria treatment Generally, no treatment is needed for acute urticaria because symptoms are usually mild and the condition is short-lived and rarely recurs. Antihistamines - However, if symptoms are more severe, or if the condition persists the patient may be given antihistamines. Antihistamines block the effects of histamines and reduce the rash and stop the itching. Current antihistamines do not make most patients drowsy. Unfortunately, some patients may be affected and should check how they react to the antihistamine before operating heavy machinery or driving a car. Antihistamines often cause drowsiness if the patient has alcohol in his/her system. Some patients may benefit from antihistamines that do cause drowsiness, especially if the itchiness is causing sleep problems. Pregnant women should not take antihistamines, unless the GP prescribes it.

Very occasionally GPs may prescribe an antihistamine called chlorphenamine for pregnant women if it is felt the benefits are greater than the risks. In the UK thousands of pregnant women have taken chlorphenamine, and so far there have been no reports of any harmful effects to the unborn baby. Corticosteroids - If symptoms are very severe the doctor may prescribe a short course of high-dose oral corticosteroids, which suppress the immune system which usually results in either eliminating or reducing the symptoms of urticaria. Corticosteroids should not be taken for more than 5 days. The longer a patient takes Corticosteroids the greater his risks are of getting an infection. Chronic urticaria treatment Patients with chronic urticaria will have treatment which is aimed at controlling symptoms and avoiding triggers that may make them worse. Patients who have chronic urticaria and angioedema should be referred to an immunologist, an allergist or a dermatologist (skin specialist doctor). Angioedema can cause breathing difficulties which can potentially cause serious problems. Patients who only have chronic urticaria and nothing else, but whose symptoms are still severe should also be referred to a specialist.

Antihistamines - antihistamines can treat the symptoms of chronic urticaria. If symptoms are causing sleep problems the patient may benefit from also taking the antihistamines that cause drowsiness. Menthol cream - this has been shown to be a useful alternative or addition to antihistamines for patients with itchiness. Corticosteroids - these may be prescribed for chronic urticaria patients whose symptoms are more severe. Avoiding triggers - as triggers can make the existing urticaria worse, it is important for the patient to identify these triggers and avoid them. Remember, that with chronic urticaria the triggers do not cause the condition, but they can make it worse. The patient may have to abstain from consuming alcohol, or cut down consumption. He/she may have to avoid certain medications as well. Avoiding stress may help - however, this may not be easy, especially if the symptoms are affecting the patient's quality of life. Some soaps may be making symptoms worse, as well as skin creams and detergents. Meditation or hypnosis - relaxation techniques, such as medication or hypnosis have been found to help reduce symptoms and levels of stress in severely affected patients.

Diet - many patients swear that certain foods make their symptoms worse. This is a controversial subject in which experts seem to have different opinions. The following foods are known to trigger histamine production - spinach, fish, yoghurt, fish, tomato, processed, meats, chocolate, and strawberries. What are the complications of urticaria? Acute urticaria complications Approximately one quarter of all patients with acute urticaria also develop acute angioedema, which should resolve itself within about three days. Patients who have breathing problems should call the emergency services immediately. Angioedema is treated with antihistamines and oral corticosteroids. Chronic urticaria complications About half of all chronic urticaria patients will get better within 3 to 5 years. One quarter of all patients will continue having symptoms for over 10 years. As with any chronic condition, the patient can become frustrated and distressed. Approximately 15% of chronic urticaria patients report feelings of depression . Patients with symptoms of depression should inform their doctor. Depression is treatable. Written by Christian Nordqvist Hives (urticaria). What are hives? Treatment for hives.

| Patient 476 Hives are itchy red or white bumps on the skin. This itchy rash is also known as urticaria, or as nettle rash. The rash may be acute (if it comes on suddenly and does not last for long) or chronic (if the rash has lasted for six weeks or more). The rash may be triggered by an allergy, or by another factor such as heat or exercise. In most cases the rash lasts 24-48 hours and is not serious. You may not require any treatment; however, medicines called antihistamines can ease the symptoms until the rash clears. What are hives? When you have hives (urticaria), you have an itchy rash caused by tiny amounts of fluid that leak from blood vessels just under the skin surface. Hives can be classed as follows: Acute - if it develops suddenly and lasts less than six weeks. Most cases last 24-48 hours. In some cases the rash only lasts a few hours. About 1 in 6 people will have at least one bout of hives in their lives. It can affect anyone at any age. Some people have recurring bouts of acute hives.

Chronic - if it persists longer than six weeks. (Chronic means persistent or ongoing.) This is uncommon. See separate leaflet called Hives (Chronic Urticaria) for more details . This rest of this leaflet deals only with hives which are acute. What does the rash of hives look like? The rash usually appears suddenly and can affect any area of skin. Small raised areas called weals (or wheals) develop on the skin. The weals look like mild blisters and they are itchy. Each weal is white or red and is usually surrounded by a small red area of skin, which is called a flare. The weal and flare rash of hives looks similar to the rash caused by a nettle sting. The weals are commonly 1-2 cm across but can vary in size. There may be just a few but sometimes many develop over various parts of the body. Sometimes weals next to each other join together to form larger ones. The weals can be any shape but are often circular. As a weal fades, the surrounding flare remains for a while. This makes the affected area of skin look blotchy and red. The blotches then fade gradually and the skin returns to normal.

Each weal usually lasts less than 24 hours. However, as some fade away, others may appear. It can then seem as if the rash is moving around the body. The rash may appear quite dramatic if many areas of skin are suddenly affected. Are there any other symptoms? Most people with hives (acute urticaria) do not feel ill; however, the appearance of the rash and the itch can be troublesome. In some cases a condition called angio-oedema develops at the same time as hives. In this condition some fluid also leaks into deeper tissues under the skin, which causes the tissues to swell. See separate leaflet called Angio-oedema for more details : The swelling of angio-oedema can occur anywhere in the body but most commonly affects the eyelids, lips and genitals. Sometimes the tongue and throat are affected and become swollen. The swelling sometimes becomes bad enough to cause difficulty breathing. Symptoms of angio-oedema tend to last longer than urticarial weals. It may take up to three days for the swollen areas to subside and go. A variation called vasculitic hives occurs in a small number of cases.

In this condition the weals last more than 24 hours, they are often painful, may become dark red and may leave a red mark on the skin when the weal goes. Technically, this type of rash is not urticaria. What causes hives? A trigger causes cells in the skin to release chemicals such as histamine. These chemicals cause fluid to leak from tiny blood vessels under the skin surface. The fluid pools to form weals. The chemicals also cause the blood vessels to open wide (dilate) which causes the flare around the weals. The trigger is not known or identified in about half of cases. Some known triggers include: Allergies - for example: Food allergies such as allergies to nuts, strawberries, citrus fruit, egg, food additives, spices, chocolate, or shellfish. Sometimes you can develop an allergy to a food even if you have eaten it without any problem many times before. Allergies to insect bites and stings. Allergies to medicines such as penicillin, aspirin, anti-inflammatory painkillers, etc. A viral infection such as a cold or flu can trigger an urticarial rash in some people.

(You react to the virus.) A mild viral infection which causes few other symptoms is probably a common trigger of an urticarial rash that develops without an apparent cause. Skin contact with certain substances causes a local area of hives in some people - for example, chemicals, latex, cosmetics, plants, ointments, nettle stings, etc. Pine tree contact: Inducible urticaria - sometimes called physical urticaria. This is a type of hives in which a rash appears when the skin is physically stimulated. The most common is called dermatographism (dermatographia) when a rash develops over areas of skin which are firmly stroked. In other cases, an urticarial rash is caused by heat, cold, emotion, exercise, or strong sunlight. See separate leaflet called Hives (Inducible Urticaria) for more details . Are hives serious? Usually not. The rash is itchy but normally fades within a day or so and causes no harm. Most people with hives (acute urticaria) do not feel too unwell unless they have a cold or flu that is triggering the rash.

The cause of the rash is not known in more than half of cases and it is commonly a one-off event. However, hives may be more serious in the following situations: Food allergy. If a food allergy is the cause then the rash is likely to return each time you eat the particular food. This is more often a nuisance than serious. Severe allergies. People who have a severe allergic reaction to peanuts, insect stings, etc, often have an urticarial rash as one of the symptoms. This is in addition to other symptoms such as severe angio-oedema, breathing difficulties, collapse, etc. A severe allergic reaction is called anaphylaxis. But note: most people with acute urticaria feel well and do not have anaphylaxis. More related content Are any tests needed? Usually no tests are needed. The rash is very typical and is easily recognised as hives by doctors. In many cases you will know what caused the rash from the events leading up to it.

(For example if you have just been put on a new medicine, or if your skin came into contact with a nettle, or if you were stung by a bee.) In some cases it may be helpful to have some allergy tests such as skin prick tests to help determine the specific cause. Sometimes blood tests for allergies can be helpful. Occasionally, if urticarial vasculitis is suspected, a sample of the skin may be taken (a skin biopsy) for further analysis. What is the treatment for hives? Often no treatment is necessary, as the rash commonly goes within 24-48 hours. A cool bath or shower may ease the itch. Calamine lotion or menthol 1% in aqueous cream can help with itching, although if it is left on for too long the itch may come back. These can be bought without a prescription. If you can identify a trigger such as a food then it would be sensible to avoid it in the future. Antihistamine tablets can ease symptoms . Antihistamines block the action of histamine which is one of the chemicals involved in causing hives. You can get antihistamines on prescription. You can also buy them without a prescription from pharmacies.

There are several types. The pharmacist will advise. The ones most often used for hives are: Fexofenadine These types of antihistamines usually work well and do not cause drowsiness. Occasionally an older antihistamine which makes you sleepy may be useful, particularly if the itch keeps you awake at night. In this case an antihistamine such as chlorphenamine may be useful. A short course of steroid tablets is sometimes prescribed in severe cases to help reduce swelling in the skin. Usually prednisolone would be the steroid used, for a short course of a few days only. If you have a severe episode of hives then you may be referred to a specialist. Skin specialists (called dermatologists) or allergy specialists (called immunologists) may be able to help. In particular, if angio-oedema or anaphylaxis occurred at the same time, you would be referred or admitted to hospital. This is to reverse the reaction quickly. It is also to confirm the diagnosis and, where possible, to identify a cause. For example, if a nut allergy is suspected to have caused a severe episode then this can confirmed by tests.

You may then be given advice on how to avoid the cause and on what to do if it should occur again. Further help & information Urticaria, Hives, Nettle rash and Angioedema - Testing & Treatment in London How can I treat urticaria? Introduction There are distinct types of urticaria called Spontaneous Urticaria and Inducible Urticaria (also known as Physical Urticaria). Ordinarily spontaneous urticaria has two patterns – Acute Urticaria and Chronic Urticaria. Acute urticaria is most often caused by an allergy to food, insect sting, viral illness or medication and can last between several hours and six weeks. Chronic urticaria is diagnosed if the rash persists or recurs for six weeks or longer, the underlying cause is then usually not due to food allergies All forms of urticaria may occur in association with deeper skin swelling or angioedema and equally, angioedema may occur in isolation with no apparent urticaria. This depends on whether we release histamine into the skin (urticaria), deeper tissues (angioedema) or both.

Angioedema swelling is most apparent in lax tissues around the eyelids, lips, tongue and genitals. This is also referred to as Angioneurotic oedema and can be associated with Anaphylactic shock. Just to confuse the issue, Chronic Urticaria may also occur together with Physical (Inducible) Urticaria. Urticaria causes Acute Urticaria The most likely cause of Acute Urticaria is an allergy due to exposure to pets, horses, latex rubber, food such as shellfish, nuts, egg and dairy products or bee and wasp stings. Allergies to medication such as antibiotics (penicillin, tetracycline, sulphonamides and cephalosporins), blood pressure pills (ACE inhibitors and diuretics), codeine and aspirin containing pain killers can cause acute urticaria. The most common cause for Acute Urticaria in a child will be a viral infection. Sometimes viral infections such as glandular fever and hepatitis B, or bacteria (helicobacter, streptococci), fungal and parasitic infections can trigger urticaria in adults.

Allergic reactions to blood products, transfusions, xray contrast and vaccines have also been implicated. Papular urticaria is the medical term for “itchy bumps” or grouped urticarial lesions seen mainly in children and which follow insect bites from midges, fleas and mosquitoes. Skeeter Syndrome is an localised allergic skin reaction to proteins from a mosquito bite. The most likely cause for acute urticaria in childhood is a viral infection. It is a popular misconception that Iodine in shellfish triggers anaphylaxis, but this is a myth as there is not enough Iodine in shellfish to trigger an allergic reaction. It is a protein in the shellfish flesh that triggers the allergy. Chronic Urticaria The cause of Chronic Urticaria is much more difficult to identify it may be inducible or spontaneous. The role of true food allergy is hardly ever a significant trigger but food additives such as salicylate, sodium benzoate, sulphites, artificial colourings and nitrites may play a role. We often end up diagnosing Chronic Spontaneous Urticaria (previously called Chronic Idiopathic Urticaria) when no cause is identified.

This condition (which can persist for many years) is due to the production of “auto-antibodies” which in turn attack specific Mast Cells in our skin and tissues causing an enormous release of histamine. Why we suddenly switch-on production of these aggressive antibodies to our own skin cells is a complete enigma. Our bodies may continue producing these auto-antibodies for a number of years leading to a great deal of distress and discomfort for the urticaria sufferer. Unfortunately over 50% of Chronic Urticaria cases are due to production of these “auto-antibodies” to the IgE and its receptor on Mast Cells found in the skin; hence there is a possible relationship to underlying thyroid and joint diseases. 30% of cases of Chronic Urticaria have underlying thyroid disease (Hashimoto’s Thyroiditis) Chronic undetected dental, sinus, urinary or parasitic infections as well as ACE inhibitor blood pressure pills (lisinopril, ramipril, enalapril and perindopril) may play a role in triggering chronic urticaria. Stress is known to aggravate urticaria and stress reduction measures are very important in treating chronic idiopathic urticaria.

A scoring system for urticaria (measuring wheals & itch) using a 7 day activity score (UAS7) has been devised. Physical Urticaria Physical urticaria or Inducible Urticaria can be triggered by physical factors such as exposure to environmental heat (prickly heat), intense cold (cold urticaria), sunlight (solar urticaria), water (aquagenic urticaria), vibration from pneumatic drills or pressure on the skin from tight clothing. Lesions typically last less than one hour. Exercise and sweating may trigger a fine itchy rash called Cholinergic Urticaria. Very rarely some people are allergic to all forms of water, this is called “Aquagenic” Urticaria. Exercising shortly after eating certain foods such as wheat, celery and shellfish might provoke delayed urticaria, asthma or even anaphylaxis. Many people have very sensitive skin and any friction or rubbing will cause raised red lines to develop (FricTest). This is called Dermatographism or Dermographia and indicates just how easily they can release histamine into their own skin.

A good test for Cold Urticaria is to hold a block of ice against the skin for 5 minutes and see if an urticaria weal develops after the ice is removed. Whereas pressing a blunt pencil against the skin for one minute will lead to a wheal developing immediately in Pressure Urticaria, while in Delayed Pressure Urticaria the wheal may only develop after 6 hours. Underlying thyroid diseases and autoimmune diseases such as Thyroiditis, Systemic Lupus and Rheumatoid Arthritis can provoke Chronic Urticaria or even Urticarial Vasculitis (a variant in which the lesions tend not to fluctuate but lead to skin bruising). Urticarial Vasculitis may be associated with a fever, bone pains and joint swelling (Schnitzler’s Syndrome). Henoch Schonlein purpura is a common “urticarial” vasculitis occuring on the lower limbs in children and occasionally children with Coeliac Disease may present with urticaria. Very often Chronic Idiopathic Urticaria will be accompanied by Physical Urticaria.

Contact Urticaria results in immediate localised skin lesions on the hands or exposed skin from direct skin contact with urticaria triggers such as latex, cosmetics, perfume and food preparation (seafood & potato) Occasionally an inherited deficiency of the C1 Esterase Inhibitor Enzyme leads to a non-itchy form of urticaria called Hereditary or Familial Angioedema. This condition affects mainly females in a family, is associated with sudden swelling of the face and neck which is painful, but there is no rash. These lesions usually last for 2 to 3 days and do not respond well to antihistamine medication. Sufferers characteristically have low levels of the Complement C4 (<0.12g/l) in their bloodstream and respond to medication such as Danazol or Tranexamic acid which prevent angioedema attacks. Isolated angio-oedema without urticaria may also be triggered by aspirin, ibuprofen, epilepsy and blood pressure medications. Urticaria symptoms Lesions tend to move about every 24 hours and “migrate” around on the body.

In chronic cases, the intense itchiness will cause sleepless nights and may lead to a depressive illness. Chronic urticaria tends to fluctuate by temporarily settling down and then suddenly relapsing again with co-existent viral illnesses, stress and aspirin containing medication such as flu remedies. This chronic pattern may recur for 5 years to 20 years in some cases! If your urticaria does not disappear after a few weeks, or does not respond to antihistamine medication, and is accompanied by any other health problem, you should go to your doctor. Blood tests may help identify an allergy or underlying immune disorder but most often all tests come back normal. A rare but troublesome cause for chronic urticaria is Systemic mastocytosis where there is a total over abundance of Mast Cells in the body with raised levels of Tryptase in the bloodstream. Localised Mast Cell overproduction in the skin is associated with excessive pigmented freckles and called Urticaria pigmentosa (then the urticaria is elicited by firmly rubbing the skin – called Darier’s sign).

Urticaria treatment Avoid any obvious triggers or exacerbating factors and try these simple measures: Keep the skin cool, avoid getting hot from exercise and take lukewarm baths. Resist the temptation to rub the itchy skin and apply copious amounts of moisturising creams to reduce dryness and itch. Avoid alcoholic drinks, anti-inflammatory drugs and foods containing additives and pseudoallergens (sodium benzoate, sulphite preservatives, colourings and salicylate). Apply 1% menthol in aqueous cream or Eurax to soothe the affected skin Avoid all aspirin or codeine containing medication (including ibuprofen, diclofenac, indomethacin, naproxen and mefenamic acid).

Only use simple paracetamol as a painkiller Avoid ACE inhibitor blood pressure pills (lisinopril, ramipril, enalapril & perindopril), if you are prone to developing urticaria and angioedema Carefully read Side Effects list of any other medication you are currently taking and avoid medicines that are known to trigger urticaria or angioedema Pregnancy may specifically aggravate urticaria as Pruritic and Urticarial Papules and Plaques of Pregnancy (PUPPP syndrome) Stress, overheating, tight clothing and alcohol may aggravate and make urticaria worse. A diet containing low-histamine containing foods (avoiding dark fish, certain vegetables, berries and strong cheeses) and other pseudoallergens (adapted Berlin Diet) may be helpful by reducing the “histamine load” on chronic urticaria. Green Tea may provoke urticaria and should be avoided. The mainstay of urticaria treatment is high dose (second generation) ANTIHISTAMINE medication which may be necessary for prolonged periods (in excess of 6 weeks).

Up to quadruple the conventional doses of these non-sedating antihistamines such as Cetirizine, Loratadine, Acrivastine and Fexofenadine may be needed to get symptom relief. The new “isomers” called desloratadine and levocetirizine don’t seen to offer any additional benefit in treating urticaria. Long-term deal steroids such as Prednisolone should be avoided due to adverse side effects. Traditionally we add “stomach-ulcer treatment” medication such as Cimetidine and Ranitidine which are known to also dampen down histamine release. Occasionally we need to add sedating antihistamines such as Chlorphenamine or Hydroxyzine at night to get urticaria control. Leukotriene receptor antagonists currently used for asthma such as Montelukast (leukotriene receptor antagonists) have provided some symptom relief in chronic urticaria when used in combination with antihistamines. Oral antidepressant Doxepin is a good antihistamine but may induced drowsiness, while Doxepin cream (if available) can soothe the skin.

Short courses of oral cortisone or steroids may be necessary for short periods (one to three days) to settle more severe symptoms and get control, however rebound urticaria after steroid use is a problem. Cortisone (Prednisolone) should not be used for prolonged periods of time as this may lead to stunted growth in children and osteoporosis in adults, therefore Kenalog (long acting)) steroid injections are discouraged. Although steroids initially suppress chronic urticaria, we find that on stopping them, the urticaria tends to rebound and become more diffficult to treat. Chlorphenamine and Loratadine are safe to use in early pregnancy, while Cetirizine and Loratadine are safe to take whilst breastfeeding. Specialist urticaria testing in Chronic Urticaria may be necessary to exclude other underlying illnesses or to confirm the presence of “auto-antibodies” in the blood stream (“Anti IgE Receptor Autoantibodies” and “Basophil Histamine Release” can be measured). The Autologous Serum Skin Test (ASST) raises a weal on re-injection of the patients serum and is a good indicator of Auto-antibodies.

Highly specialised third line treatments may include Immunosuppressive drugs such as Ciclosporin (autoimmune urticaria), Methotrexate (non-autoimmune urticaria), and Sulphasalazine (Pressure urticaria). Androgen hormones, Thyroxine, Nifedipine and Warfarin have been used with variable efficacy as well. Colchicine and Dapsone are useful in treating Urticarial Vasculitis. If available, Immunoglobulin injections, Plasmaphoresis have been used. The use of a novel asthma drug, the anti-IgE monoclonal antibody Omalizumab (Xolair) may be necessary if no other treatment is effective. Although expensive at £ 500 per month, the drug is very effective at clearing chronic urticaria and has been approved as third line therapy for Chronic Urticaria by the US FDA and UK NICE guidelines. However when the treatment is stopped , the urticaria tends to recur. Reference: Powell RJ, Leech S, Till S et al, BSACI guidelines for the management of chronic urticaria and angio-oedema.

Clin Exp Allergy 2015: 45; 547-565. Greaves MW, Kaplan AP. Urticaria and Angioedema (Marcel Dekker 2004) Copyright Dr Adrian Morris Nettle rash - Treatment Treatment Urticaria (Hives) Acute urticaria Treatment for acute urticaria may not be required, as the symptoms are mild and the condition can get better on its own within a few days and not return. If the symptoms of acute urticaria are more serious or the condition persists,Â you can consult your pharmacistÂ and buy an antihistamineÂ over the counter, or consult your GP for a prescription of antihistamines (see below). Your GP may also prescribe you corticosteroid tablets if symptoms are severe. Return to your GP if the symptoms get worse or there is no response to treatment after two weeks. Antihistamines Antihistamines block the effects of histamine, so they should stop the symptoms of itchiness and reduce the rash.

Examples of antihistaminesÂ include: cetirizine fexofenadine loratadine Modern antihistamines do not cause drowsiness in most people, but there are some exceptions.Â See how you react to the antihistamine before driving or operating heavy machinery. Modern antihistamines may cause drowsiness if taken with alcohol.Â Always read the information leaflet for your medication. If you are having problems sleeping at night due to particularly itchy urticaria, your GP may give you additional antihistamines that are known to cause drowsiness, such as chlorphenamine or hydroxyzine. Antihistamines are normally not prescribed during pregnancy. This is because they have not been established as being entirely safe. However, your GP may recommend chlorphenamine if they feel that the benefits outweigh the risk. There are several thousand known cases of pregnant women taking chlorphenamine, and there is no evidence that it harmsÂ unborn babies. Corticosteroid tablets You may beÂ prescribed a short course of high-dose corticosteroid tablets, such as prednisolone. Corticosteroids suppress your immune system and therefore can suppress the symptoms of urticaria.

Possible side effects of corticosteroid tablets include increased appetite and weight gain, mood changes andÂ insomnia. Chronic urticaria Treatment for chronic urticaria involves helping you to control your symptoms and avoiding any triggers that make the symptoms worse. If you have chronic urticaria and angioedema, you should be referred to an immunologist (a specialist in the immune system), an allergist or a dermatologist (a specialist in skin conditions). This is because angioedema is potentially more serious as it can cause breathing difficulties. If you only have chronic urticaria but the symptoms persist despite treatment, you should also be referred. Antihistamines The symptoms of chronic urticaria is treated with antihistamines. You may have to take them regularly for as long as the symptoms last. As with acute urticaria, you may be given a combination of 'non-drowsy' and 'drowsy' antihistamines to help you sleep. Menthol cream Menthol cream can be used as an alternative or in addition to antihistamines as it has been shown to relieve itchiness. Your GP can prescribe this.

Corticosteroid tablets More serious episodes of urticaria can be treated with short doses of corticosteroid tablets, such as prednisolone. Possible side effects of corticosteroid tablets include increased appetite and weight gain, mood change,Â and insomnia. Long-term use of corticosteroids in chronic urticaria is not recommended. Diet There is controversy over the role of diet in people with chronic urticaria.Â There are two groups of chemicals in foods that may trigger urticaria: vasoactive amines and salicylates. Avoiding or reducing the intake of these chemicals mayÂ possibly improve the symptoms. You may wish to keep a food diary to see if avoiding a certain food helps your symptoms. If you restrict your diet, consultÂ a dietitian, who can make sure that you are not avoiding foods unnecessarily, and that your diet is adequate. Vasoactive amines: Foods that contain vasoactive amines, or cause histamine release, include: shellfish Stinging nettle | University of Maryland Medical Center Stinging nettle is used in many forms, including as teas, tinctures, fluid extracts, and creams.

Precautions The use of herbs is a time-honored approach to strengthening the body and treating disease. However, herbs can trigger side effects, and can interact with other herbs, supplements, or medications. For these reasons, you should take herbs with care, under the supervision of a health care provider. Stinging nettle is generally considered safe when used as directed. Occasional side effects include mild stomach upset, fluid retention, sweating, diarrhea, and hives or rash (mainly from topical use). It is important to be careful when handling the nettle plant because touching it can cause an allergic rash. Stinging nettle should never be applied to an open wound. Because nettle can alter the menstrual cycle and may contribute to miscarriage, pregnant women should not use nettle. Do not self treat with nettle for BPH. See your doctor to receive a diagnosis and to rule out prostate cancer. There is some evidence that stinging nettle may raise blood sugar and interfere with diabetes management. There is also evidence that it can lower blood sugar. Patients with diabetes should monitor their blood sugar closely when using stinging nettle. Stinging nettle can have a diuretic effect.

If you have kidney or bladder issues, speak with your health care provider.

Possible Interactions Antiplatelet and anticoagulant drugs (blood thinners) -- Stinging nettle may affect the blood's ability to clot, and could interfere with blood-thinning drugs, including: Warfarin (Coumadin) Clopidogrel (Plavix) Aspirin Drugs for high blood pressure -- Stinging nettle may lower blood pressure, so it could strengthen the effects of these drugs: ACE inhibitors: Captopril (Capoten), Elaropril (Vasotec), lisinopril (Zestril), fosinopril (Monopril) Beta-blockers: Atenolol (Tenormin), metoprolol (Lopressor, Toprol XL), propranolol (Induran) Calcium channel blockers: Nifedipine (Procardia), amlodipine (Norvasc), verapamil (Calan, Isoptin) Diuretics (water pills) -- Because stinging nettle can act as a diuretic, it can increase the effects of these drugs, raising the risk of dehydration: Furosemide (Lasix) Hydrocholorothiazide Drugs for diabetes -- Stinging nettle may lower blood sugar

, so it could strengthen the effects of these drugs, raising the risk of hypoglycemia (low blood sugar).

Lithium -- Stinging nettle may have a diuretic effect and may reduce the body's ability to remove this drug. Nonsteroidal anti-inflammatory drugs (NSAIDs) -- In a scientific study of patients with acute arthritis, stewed stinging nettle leaves enhanced the anti-inflammatory effect of diclofenac, an NSAID. Although this effect can reduce pain, talk to your doctor before taking or using stinging nettle if you also take NSAIDs. Supporting Research Blumenthal M, Goldberg A, Brinckmann J. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Integrative Medicine Communications; 2000:367-375. Bone K, Mill S, eds. Principles and Practices of Phytotherapy, Modern Herbal Medicine. London: Churchill Livingstone; 2000. Chrubasik JE, Roufogalis BD, Wagner H, Chrubasik S. A comprehensive review on the stinging nettle effect and efficacy profiles. Part II: urticae radix. Phytomedicine. 2007;14:568-79. Ernst E, Chrubasik S.

Phyto–anti-inflammatories. A systematic review of randomized, placebo-controlled, double-blind trials. Rheum Dis Clin North Am. 2000;26:13-27. Helms S, Miller A. Natural treatment of chronic rhinosinusitis. Altern Med Rev. 2006;11:196-207. Johnson TA, Sohn J, Inman WD, Bjeldanes LF, Rayburn K. Lipophilic stinging nettle extracts possess potent antiinflammatory activity, are not cytotoxic and may be superior to traditional tinctures for treating inflammatory disorders. Phytomedicine. 2013; 20:143-7. Koch E. Extracts from fruits of saw palmetto (Sabal serrulata) and roots of stinging nettle (Urtica dioica): viable alternatives in the medical treatment of benign prostatic hyperplasia and associated lower urinary tract symptoms. Planta Med. 2001;67:489-500. Konrad L, Muller HH, Lenz C, Laubinger H, Aumuller G, Lichius JJ.

Antiproliferative effect on human prostate cancer cells by a stinging nettle root (Urtica dioica) extract. Planta Med. 2000;66:44-7. Lopatkin NA, Sivkov AV, Medvedev AA, Walter K, Schlefke S, Avdeichuk IuI, et al. Combined extract of Sabal palm and nettle in the treatment of patients with lower urinary tract symptoms in double blind, placebo-controlled trial. Urologiia. 2006;:12, 14-9. Nahata A. Ameliorative effects of stinging nettle (Urtica dioica) on testosterone-induced prostatic hyperplasia in rats. Andrologia. 2012; 44:396-409. Pittler MH. Complementary therapies for treating benign prostatic hyperplasia. FACT. 2000;5:255-257. Popa G, Hagele-Kaddour H, Walther C.

Efficacy of a combined Sabal-urtica preparation in the symptomatic treatment of benign prostatic hyperplasia. Results of a placebo-controlled double-blind study. MMW Fortschr Med. 2005;147 Suppl 3:103-8. Rakel D. Integrative Medicine, 3rd ed. Philadelphia, PA: Elsevier Saunders;2012:70. Randall C, Randall H, Dobbs F, Hutton C, Sanders H. Randomized controlled trial of nettle sting for treatment of base-of-thumb pain. J R Soc Med. 2000;93:305-309. Safarinejad MR. Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study. J Herb Pharmacother. 2005;5:1-11. Schneider T, Rubben H. Stinging nettle root extract (Bazoton-uno) in long term treatment of benign prostatic syndrome (BPS). Results of a randomized, double-blind, placebo controlled multicenter study after 12 months.

Urologe A. 2004;43:302-6. Schulze-Tanzil G, de SP, Behnke B, Klingelhoefer S, Scheid A, Shakibaei M. Effects of the antirheumatic remedy hox alpha – a new stinging nettle leaf extract – on matrix metalloproteinases in human chondrocytes in vitro. Histol Histopathol 2002;17:477-485. Tarhan O, Alacacioglu A, Somali I, Sipahi H, Zencir M, Oztop I, Dirioz M, Yilmaz U. Complementary-alternative medicine among cancer patients in the western region of Turkey. J BUON. 2009;14:265-9. Wilt TJ, Ishani A, Rutks I, MacDonald R. Phytotherapy for benign prostatic hyperplasia. Public Health Nutr. 2000;3:459-472.

Alternative Names Definition of Hives Our Hives (Urticaria & Angioedema) Main Article provides a comprehensive look at the who, what, when and how of Hives (Urticaria & Angioedema) Definition of Hives Nasal Allergy Relief Products Slideshow Hives: A raised, itchy area of skin that may be a sign of an allergic reaction. It can be rounded or flat-topped but is always elevated above the surrounding skin. It reflects circumscribed dermal edema (local swelling of the skin). The hives are usually well circumscribed but may be coalescent and will blanch with pressure. A single spot is almost always gone by 24 hours but the process may stay for weeks to months. Approximately 20% of the population has experienced a bout of hives. The hives are also called urticaria. Last Editorial Review: 5/13/2016

Question: What is the medical namefor hives, or nettle rash?
Answer: URTICARIA