context: You might have an itch that must be scratched. Or a tickle on your back that you can't reach. It's often hard to pin down just what's causing it. It may be as simple as the clothes you wear. But it can also be a symptom of something more serious, like a rash or an illness. Start with the simplest solutions. Try a different fabric, take care of your skin, and avoid anything that seems to trigger the itch. If that doesn't help, ask your doctor, who will check on the cause and the treatment you need. Is Your Skin Dry? If your skin is dry, it will let you know with an itch. It can be especially bad in the winter and in places where the air is dry. As you get older, it becomes even more common. To ease the itch of dry skin: Use moisturizer after you bathe while your skin is still damp. Drink lots of fluids to stay hydrated. Use a humidifier. Make your shower quick, and don't use very hot water. Use mild soaps. Learn more about how to prevent itching caused by dry skin. Is There a Rash? If you start scratching and find a rash, it's likely the problem is in your skin. It can happen because of: Fungal and bacterial infections like impetigo and folliculitis. See a photo of what impetigo looks like. Bugs: When you get bitten by a mosquito or spider, you know it. Bites from bedbugs and mites can be harder to diagnose because they look like rashes. Lice can cause a crawling sensation in your scalp or pubic hair, along with an intense itch. See a photo of what bedbug bites look like. Eczema or atopic dermatitis: It shows up on your skin as dry, scaly patches or a bumpy rash. It isn't clear what causes it, but it's extremely itchy. Kids are more likely to get it if their family has a history of asthma and allergies. Certain food allergies can make it worse. So does scratching. See a photo of what eczema looks like. Contact dermatitis: This itchy rash is caused by a reaction to something touching your skin. You may have to do some detective work to figure out where it's coming from. It could be the metals in your jewelry or the chemicals in cosmetics, toiletries, and cleaning products. Poison ivy is also a form of contact dermatitis. Stop using or wearing whatever you think might be the cause and see if the itching gets better. See a photo of what a poisonous plant rash looks like. Is It Beneath the Surface? Your skin may let you know when something is not quite right inside your body. This itch can be a symptom of deeper problems. Hives: You get them from allergies. They look like raised welts that show up alone or in clusters, and they are usually itchy. Stress, heat, exercise, or exposure to the sun can also bring them out. See a photo of what hives look like. Psoriasis: It makes your body overproduce skin cells, which pile up in itchy, inflamed patches on the skin's surface. This is a result of an overactive immune system. See a photo of what psoriasis looks like. Pregnancy: More than 1 in 10 pregnant women say itching is a problem. The reasons range from harmless rashes to more serious conditions. Learn more about skin conditions in pregnancy. Medications: Some may make your skin itch, even with no signs of a rash or irritation. Check with your doctor if the itch becomes too uncomfortable. These drugs are known to make you start scratching. Certain high blood pressure drugs called ACE inhibitors Allopurinol for gout Amiodarone for heart rhythm problems Pills called diuretics that relieve bloating Estrogen Hydroxyethyl cellulose (used during surgery) Prescription pain drugs called opioids Simvastatin for high cholesterol Is It Related to Your Nerves? Your nervous system can get confused when it's sick and accidentally tell the nerves on the skin to start itching when there's nothing there to cause it. There is no rash. But your skin may appear irritated if you've been scratching a lot. You can get it from: Shingles Multiple sclerosis Stroke Brain tumor Nerve damage Is It Psychological? If your doctor can't find a physical cause, it may be in your mind. Some mental conditions give people the urge to scratch or pick at themselves. They may feel like their skin is crawling with something. There is no rash, but there may be skin damage from scratching. Compulsive scratching can be a sign of: Depression Anxiety Obsessive-compulsive disorder Psychosis Trichotillomania Learn more about skin picking disorder. Unlikely, but Possible Itchiness usually has a simple, common cause. But in some cases, if it doesn't go away, could be a sign of a serious illness, such as: Kidney disease Liver disease Thyroid problems Certain cancers, particularly Hodgkin's disease Diabetes Iron deficiency HIV You might also start itching after the treatments for some of these illnesses. Kidney dialysis, chemotherapy, and radiation therapy have it as a side effect. Learn more about chemotherapy side effects.