Hyperpigmentation and Hypopigmentation: Albinism, Vitiligo, and More Pigmentation is the coloring of a person's skin . When a person is healthy, his or her skin color will appear normal. In the case of illness or injury, the person's skin may change color, becoming darker (hyperpigmentation) or lighter (hypopigmentation). Hyperpigmentation and Skin Hyperpigmentation in skin is caused by an increase in melanin, the substance in the body that is responsible for color (pigment). Certain conditions, such as pregnancy or Addison's disease (decreased function of the adrenal gland), may cause a greater production of melanin and hyperpigmentation. Exposure to sunlight is a major cause of hyperpigmentaion, and will darken already hyperpigmented areas. Hyperpigmentation can also be caused by various drugs, including some antibiotics , antiarrhythmics, and antimalarial drugs. Melasma An example of hyperpigmentation is melasma (also known as chloasma). This condition is characterized by tan or brown patches, most commonly on the face. Melasma can occur in pregnant women and is often called the "mask of pregnancy;" however, men can also develop this condition.

Melasma sometimes goes away after pregnancy. It can also be treated with certain prescription creams (such as hydroquinone ). If you have melasma, try to limit your exposure to daylight. Wear a broad-brimmed hat and use a sunscreen with an SPF of 30 or higher at all times, because sunlight will worsen your condition. Sunscreens containing the physical blockers zinc oxide or titanium dioxide are also helpful in blocking daylight’s UVA rays, which makes hyperpigmentation worse. Consult with your doctor before treating the condition yourself. Hypopigmentation and Skin Hypopigmentation in skin is the result of a reduction in melanin production. Examples of hypopigmentation include: Vitiligo : Vitiligo causes smooth, white patches on the skin. In some people, these patches can appear all over the body. It is an autoimmune disorder in which the pigment-producing cells are damaged. There is no cure for vitiligo, but there are several treatments, including cosmetic cover-ups, corticosteroid creams, or ultraviolet light treatments. Albinism : Albinism is a rare inherited disorder caused by the absence of an enzyme that produces melanin.

This results in a complete lack of pigmentation in skin, hair , and eyes . Albinos have an abnormal gene that restricts the body from producing melanin. There is no cure for albinism. People with albinism should use a sunscreen at all times because they are much more likely to get sun damage and skin cancer . This disorder can occur in any race, but is most common among whites. Pigmentation loss as a result of skin damage: If you've had a skin infection, blisters , burns, or other trauma to your skin, you may have a loss of pigmentation in the affected area. The good news with this type of pigment loss is that it's frequently not permanent, but it may take a long time to re-pigment. Cosmetics can be used to cover the area, while the body regenerates the pigment. Continued Human Biological Adaptability: Skin Color as an Adaptation is essentially unable to tan While skin tanning is often most noticeable on light complexioned people, even those with very dark brown skin can tan as a result of prolonged exposure to the sun. Some Northwest Europeans have substantially lost the ability to tan as a result of relaxed natural selection.

Their skin burns and peels rather than tans. This is due to the fact that they produce a defective form of a skin protein Mc1r (melanocortin-1 receptor) which is necessary for the production of melanin. They are at a distinct disadvantage in tropical and subtropical environments. Not only do they suffer the discomfort of readily burning, but they are at a much higher risk for skin cancer. The same is true of albinos . It would be harmful if melanin acted as a complete shield. A certain amount of shortwave ultraviolet radiation (UVB) must penetrate the outer skin layer in order for the body to produce vitamin D. Approximately 90% of this vitamin in people normally is synthesized in their skin and the kidneys from a cholesterol-like precursor chemical with the help of ultraviolet radiation. The remaining 10% comes from foods such as fatty fish and egg yolks. Simple vitamin D is converted by our bodies into two sequential forms. The last form, commonly referred to as vitamin D3, is needed for the intestines to absorb calcium and phosphorus from food for bone growth and repair.

Calcium is also necessary in adults to maintain normal heart action, blood clotting, and a stable nervous system. New evidence suggests that vitamin D may help prevent a wide range of cancers, including those of the colon and breasts. Vitamin D plays an additional important role in promoting the production of cathelicidin, which helps to defend our bodies against fungal, bacterial, and viral infections, including the common flu. Too much ultraviolet radiation penetrating the skin may cause the breakdown of folate in the body, which can cause anemia . Folate is derived from folic acid (one of the B vitamins) in our food. Pregnant women who are deficient in folate are at a higher risk of having miscarriages and babies with neural tube defects . Because folate is needed for DNA replication in dividing cells, its absence can have an effect on many body processes, including the production of sperm cells. It may be that the ability to produce melanin was selected for in our early human ancestors because it helped preserve the body's supply of folate in addition to reducing the chances of developing skin cancer. People who live in far northern latitudes, where solar radiation is relatively weak most of the year, have an advantage if their skin has little shielding pigmentation.

Nature selects for less melanin when ultraviolet radiation is weak. In such an environment, very dark skin is a disadvantage because it can prevent people from producing enough vitamin D, potentially resulting in rickets disease in children and osteoporosis in adults. Contributing to the development of osteoporosis in older people is the fact that their skin generally loses some of its ability to produce vitamin D. Women who had prolonged vitamin D deficiencies as girls have a higher incidence of pelvic deformities that prevent normal delivery of babies. The Inuit people of the American Subarctic are an exception. They have moderately heavy skin pigmentation despite the far northern latitude at which they live. While this is a disadvantage for vitamin D production, they apparently made up for it by eating fish and sea mammal blubber that are high in vitamin D. In addition, the Inuit have been in the far north for only about 5,000 years. This may not have been enough time for significantly lower melanin production to have been selected for by nature. In the United States and other developed nations, milk is now usually fortified with vitamins D and A in order to prevent developmental problems such as those described above.

However, the popularity of carbonated soft drinks and other alternatives to milk along with a decrease in the amount of time spent outdoors has led to a considerable rise in the rate of rickets disease. Not surprisingly, vitamin D deficiency is most acute in the winter in temperate and colder zones, especially among people of African ancestry. There is a growing epidemic of vitamin D deficiency in the United States. The 2007-2008 "National Government Health and Nutrition Examination Survey" found that only 23% of teens and adults had a sufficient amount of this essential vitamin in their blood. It was 45% a decade earlier. The rate for African Americans in particular was far worse. It has dropped from 12% to only 3% having what doctors consider to be an adequate amount of vitamin D for overall good health. Given this difference, it is not surprising that 15% African American women have pelvis deformities, while the rate among European Americans is only 2%. There is also a strong correlation between the amount of sunlight that children are exposed to and whether or not they will develop multiple sclerosis as adults.

Most cases of this degenerative neural disorder are in the temperate regions of the world where the sunlight is rarely intense. Children growing up in tropical and subtropical regions rarely develop MS regardless of where their ancestors came from. This protection apparently continues for those who move to far northern or far southern regions after 16 years of age. What processes are responsible for this protection from MS and its possible relationship to skin color are unknown. New research by Nina Jablonski and George Chaplin has led to the discovery that women generally produce 3-4% less melanin in their skin than do men in all populations of the world. They suggest that this is probably due to the fact that women have far higher calcium requirements during their reproductive years. Mate selection preference and other cultural practices may also be partly responsible for this gender difference in skin coloration. Nina Jablonski breaks the illusion of skin color --explanation of why humans have a wide variation in skin color around the world. This link takes you to an external website. To return here, you must click the "back" button on your browser program.

(length = 14 mins, 46 secs) Skin Color Distribution Around the World Before the mass global migrations of people during the last 500 years, dark skin color was mostly concentrated in the southern hemisphere near the equator and light color progressively increased farther away, as illustrated in the map below. In fact, the majority of dark pigmented people lived within 20� of the equator. Most of the lighter pigmented people lived in the northern hemisphere north of 20� latitude, where ultraviolet radiation is much less intense on average. (Data for native populations collected by R. Biasutti prior to 1940.) Such a non-random distribution pattern of human skin color was predicted by Constantin Wilhelm Lambert Gloger, a 19th century German zoologist. In 1833, he observed that heavily pigmented animals are to be found mostly in hot climates where there is intense sunshine. Conversely, those in cold climates closer to the poles commonly have light pigmentation. Presumably, the relative intensity of solar radiation is largely responsible for this distribution pattern. There are exceptions to Gloger's rule in the animal kingdom.

In some species the survival value of having a camouflaged body can be more important than the selective pressures of ultraviolet radiation. This is the case with arctic hares, which are white like snow in the winter and mottled black, brown, and gray similar to the rocky ground in their region after the snow melts in the summer. These color changes make it more difficult for arctic foxes to prey on them. Among humans, mate selection preferences may counter some of the evolutionary trend in skin color predicted by Gloger. Ultraviolet radiation is also blocked to some degree by hair, clothing, smog, fog, smoke, clouds, and trees. The Inuit case described earlier suggests that diet may additionally be a significant factor in some societies. NEWS: In the February 2007 issue of the Journal of Nutrition, a research team led by Lisa Bodnar of the University of Pittsburgh School of Public Health reported that among 400 first-time pregnant women from that city who participated in their study, only 16.1% of African Americans and 52.9% of European Americans had sufficient amounts of vitamin D in their blood to be considered healthy at the end of their pregnancies.

This was despite the fact that more than 90% of them had regularly taken standard doses of prenatal vitamin supplements. Tests of umbilical cord blood indicated that only 7.6% of the African American infants and 33.9% of the European American ones had adequate amounts of vitamin D at birth. The authors concluded that prenatal vitamins should include higher doses of vitamin D, especially in the northern regions of the U.S. Human Skin Color Variation | The Smithsonian Institution's Human Origins Program Human Skin Color Variation Home » Human Evolution Evidence » Genetics » Human Skin Color Variation » Modern Human Diversity - Skin Color Modern Human Diversity - Skin Color Why do people from different parts of the world have different colored skin? Why do people from the tropics generally have darker skin color that those who live in colder climates? Variations in human skin color are adaptive traits that correlate closely with geography and the sun’s ultraviolet (UV) radiation. As early humans moved into hot, open environments in search of food and water, one big challenge was keeping cool. The adaptation that was favored involved an increase in the number of sweat glands on the skin while at the same time reducing the amount of body hair.

With less hair, perspiration could evaporate more easily and cool the body more efficiently. But this less-hairy skin was a problem because it was exposed to a very strong sun, especially in lands near the equator. Since strong sun exposure damages the body, the solution was to evolve skin that was permanently dark so as to protect against the sun’s more damaging rays. Melanin, the skin's brown pigment, is a natural sunscreen that protects tropical peoples from the many harmful effects of ultraviolet (UV) rays. UV rays can, for example, strip away folic acid, a nutrient essential to the development of healthy fetuses. Yet when a certain amount of UV rays penetrates the skin, it helps the human body use vitamin D to absorb the calcium necessary for strong bones. This delicate balancing act explains why the peoples that migrated to colder geographic zones with less sunlight developed lighter skin color. As people moved to areas farther from the equator with lower UV levels, natural selection favored lighter skin which allowed UV rays to penetrate and produce essential vitamin D. The darker skin of peoples who lived closer to the equator was important in preventing folate deficiency.

Measures of skin reflectance, a way to quantify skin color by measuring the amount of light it reflects, in people around the world support this idea. While UV rays can cause skin cancer, because skin cancer usually affects people after they have had children, it likely had little effect on the evolution of skin color because evolution favors changes that improve reproductive success. There is also a third factor which affects skin color: coastal peoples who eat diets rich in seafood enjoy this alternate source of vitamin D. That means that some Arctic peoples, such as native peoples of Alaska and Canada, can afford to remain dark-skinned even in low UV areas. In the summer they get high levels of UV rays reflected from the surface of snow and ice, and their dark skin protects them from this reflected light. Vitiligo Symptoms, Causes, Treatments, White Spots on Skin, & More Vitiligo is a condition in which white patches develop on the skin . Any location on the body can be affected and most people with vitiligo have white patches on many areas of the body. Causes of Vitiligo Melanin is the pigment that gives the skin its characteristic color.

Vitiligo is caused by a loss of pigment in the skin, due to destruction of pigment-forming cells known as melanocytes. The exact cause of the destruction of these cells is not known. One possible explanation might be that the body's immune system destroys the cells, as in other autoimmune conditions. Although vitiligo affects all races equally, it is more noticeable in dark-skinned people. Risk Factors for Vitiligo Vitiligo affects up to 2% of the population, and it is estimated that two to five million Americans have the condition. In most cases, vitiligo develops early in life, between the ages of 10 and 30 years. Ninety-five percent of those affected will develop the disorder before age 40. Both men and women are equally likely to develop vitiligo. Vitiligo may run in families; those with a family history of vitiligo or premature graying of the hair are at increased risk for the development of vitiligo. Other risk factors that increase one's chances of developing vitiligo include having autoimmune diseases , such as autoimmune thyroid disease ( Hashimoto's thyroiditis ).

Symptoms of Vitiligo Symptoms of vitiligo include an often rapid pigment loss on several areas of the skin. The initial appearance of the white patches can be followed by a stable period without any progression of the condition. Later on, further cycles of pigment loss and stability may be observed. Vitiligo commonly affects areas on the skin that are exposed to sun, body folds (such as armpits), previous sites of injury, areas around moles, or areas around body openings. It is rare for pigment to return once the white patches have developed. Vitiligo can also affect the eyelids and hair . Diagnosis and Treatment of Vitiligo Your doctor can usually make the diagnosis of vitiligo during a physical exam . There is no known way to prevent or cure vitiligo. However, several methods, including cosmetics , re-pigmentation using UV light therapy, corticosteroid creams, depigmentation of unaffected skin areas, and skin grafting, can be used to improve the appearance of skin severely affected by vitiligo. WebMD Medical Reference Reviewed by Debra Jaliman, MD on June 11, 2015 Sources Skin Color Changes Skin Color Changes Causes What are skin color changes?

Skin color changes include any discoloration of the skin in a patchy or uniform pattern. Skin color changes can include red, yellow, purple, blue, brown (bronze or tan), white, green, and black coloring or tint to the skin. Skin can also become lighter or darker than normal. Types of skin color changes Possible skin color changes include: Blotchy red spots Bruising or bleeding under the skin Change in appearance of a mole or other birthmark Darkening (hyperpigmentation), such as darkening of the facial skin Flushing (redness) Jaundice (yellowing of skin and eyes) Mottled or marbled appearance Pale bluish or grayish skin tone (cyanosis), which can also affect the lips and nails Patchy skin color changes, such as patches of white skin (vitiligo) Tiny red or purple spots (petechiae) Unusually light skin color (hypopigmentation) Pigment-producing cells in the skin called melanocytes give skin its color. Melanocytes produce a pigment called melanin. Lighter skin, or hypopigmented skin, produces less melanin, while darker areas of skin, or hyperpigmented skin, produce more melanin.

Your skin may be naturally light or dark depending on how much melanin your skin produces. Changes in melanin production can be caused by changing hormone levels and medications. Looking for a Doctor? Search Now Find a Great Dermatologist Near You Although melanin pigment is brown, its appearance changes hue the deeper it rests in the skin. This is due to an optical phenomenon called the Tyndall effect. Deep patches of melanin may look green, grey, even blue. Changes in skin color can also accompany a variety of disorders, diseases and conditions, including inflammation, malignancy (cancer), organ failure, allergies, and infections. Changes in skin color can occur suddenly or gradually. The color can be blotchy and affect only a small area of the skin, such as a rash on your chest, or you may have a uniform change over the entire body, such as redness or jaundice (yellowing of the skin and eyes). Skin color changes can be caused by a serious, potentially life-threatening condition, such as an allergic reaction, infection, or cancer. A rash of tiny purple spots on the skin can be due to meningitis or allergic purpura, both of which can be life threatening.

Seek immediate medical care (call 911) if you, or someone you are with, have these symptoms or other serious symptoms, such as a change in consciousness, or hives or a rash accompanied by wheezing, shortness of breath, or swelling of the face, mouth or throat. Overview of Skin Pigment - Skin Disorders - Merck Manuals Consumer Version Overview of Skin Pigment Melasma Melanin is the brown pigment that produces the various shades and colors of human skin. Coloration (pigmentation) is determined by the amount of melanin in the skin. Without melanin, the skin would be pale white with shades of pink caused by blood flow through the skin. Fair-skinned people produce very little melanin, darker-skinned people produce moderate amounts, and very dark-skinned people produce the most. People with albinism have little or no melanin and thus their skin appears white or pale pink. Usually, melanin is fairly evenly distributed in the skin, but sometimes people have spots or patches of skin with more melanin. Examples of such spots include freckles, age spots ( lentigines ), and melasma .

Melanin is produced by specialized cells (melanocytes) that are scattered among the other cells in the top layer of the skin called the epidermis. After melanin is produced, it spreads into other nearby skin cells. Pigment disorders Pigment disorders can be widespread and affect many areas of skin, or they can be localized and affect only certain areas of the skin. The pigmentation changes they cause are called Depigmentation Humans | Causes of Color Never burns, but tans very darkly. African Americans, Africans, or dark-skinned individuals with heavy pigmentation. Balancing the benefits and the dangers of ultraviolet radiation for differing climates The darkest skin tones are found in tropical latitudes with open grassland, while areas further from the equator that are forested tend to favor lighter skin tones There is a striking correlation between geographic conditions, particularly exposure to sunlight, and skin tone. These differences have evolved to find the balance between the benefits and the dangers of the ultraviolet (UV) radiation we absorb from the sun. Early humankind living in the sun-soaked savannah plains of Africa developed a dark-toned skin, rich in the pigment melanin.

Within the skin cells, melanin concentrates above the nucleus, shielding the vital DNA from radiation damage. In an environment where there is little to break the path of sunlight onto the skin, this barrier is a great advantage. There are other benefits to having a high concentration of melanin in the skin and other parts of the body. Melanin boosts the immune system, and darker-skinned groups have been shown to have a lower incidence of a number of serious diseases, including Parkinson’s, multiple sclerosis, and spina bifida. Darker-skinned individuals also age better, as their skin is better protected from sun damage. Vitamin D and skin color: finding a balance It is the UV component of sunlight that helps the body utilize vitamin D. This vitamin helps promote bone growth, maintaining the right balance between calcium and phosphorus in the body. A deficiency of vitamin D leads to rickets and similar diseases. It seems that, as early peoples migrated away from the equator into areas less exposed to the sun, there was not enough UV radiation to produce sufficient vitamin D to prevent diseases such as rickets. Their bodies compensated by producing less melanin, so that more sunlight would be allowed through. They could then produce sufficient vitamin D with less exposure to sunlight.

Light-skinned people visiting sunny locations may not have enough melanin to block the sun sufficiently, and may burn their skin without the protection of sunblock. Dark-skinned people visiting areas where there is less exposure to the sun may apparently not produce enough vitamin D, but can get it from supplements or food sources. Many foods such as milk and bread are now vitamin D fortified. As the distribution map of skin color shows, skin color variation is not deter mined purely by distance from the equator. For example, people in snow-covered areas often have a dark skin tone. This may be because they are exposed to high levels of reflected UV radiation from the snow, or because their diet with its high proportion of fish is rich in vitamin D. Grains in breads and cereals are often fortified with vitamin D. Fish is a natural source of vitamin D. Light skin becomes darker when exposed to ultraviolet radiation. Tanning: darkening light skin The popularity of tanning seems cyclical, alternately being perceived as a healthy vibrant look and as a worrying reminder of the dangers of sunburn and carcinogenic melanomas. Light skin becomes darker upon exposure to ultraviolet radiation.

Sunshine is the primary source of UV radiation, but artificial sources such as tanning beds produce similar effects. Skin is alive, so when melanin is destroyed by UV ra diation, the skin responds to this damage. Skin cells will produce more melanin, replacing what has been lost and increasing the percentage of melanin in the skin. This melanin has two effects, acting as a barrier to protect the skin from further damage, and darkening the natural color of the skin. Ultraviolet light produced in a tanning bed causes the same effect. Melanogenesis is the name of the process where melanins are produced by specialized pigment cells called melanocytes, in response to UV radiation. Melanin in our skin protects our DNA from damage by UV radiation. This creates a long-lasting tan. A tan effect is also created when existing melanin is oxidized, but this doesn’t last as long. Regular tanning beds use several fluorescent lamps (see light bulbs and lamps ) that have phosphor blends designed to emit UV in a spectrum that is somewhat similar to the sun. The radiation produced is primarily UVA, with some UVB always being emitted, but the combinations of UVA and UVB can vary.

Tanning bulbs are long fluorescent tubes, and fall into two main categories: low pressure lamps and high-pressure bulbs. Each bulb typically has a power between 100W and 200W. Alternative designs use high-powered parabolic lamps. The number of bulbs used by tanning beds vary: those designed for the home use 20 to 30 bulbs, commercial beds use 30 to 40 bulbs, and specialist stand-up booths use as many as 60 bulbs. Tanning bed A tanning bed or sun bed (whether at home or in a salon) is a device emitting ultraviolet radiation used to produce a cosmetic tan. The World Health Organization (WHO) does not recommend the use of UV tanning devices for cosmetic reasons. Overexposure to UV radiation from the sun and artificial sources is of considerable concern for its adverse effects on health. UV radiation plays an important role in the development of skin cancer, cataracts, (see colorblindness ), and other eye conditions. It also suppresses the immune system. Cumulative UV radiation ages the skin prematurely. Tanning lotions An alternative method of darkening the skin is the use of tanning lotions.

These lotions use a wide range of active ingredients. One of the original sunless tanning lotions caused streaking and an orange skin tone, which gave the fake tan a bad reputation. Lotions that contain dihydroxyacetone (DHA) as the active ingredient are used in many sunless tanning products. DHA, which is derived from plant sources like sugar beets and sugar cane, is a colorless sugar that interacts with the dead cells located in the stratum corneum of the epidermis. As the sugar interacts with the dead skin cells, a color change occurs. This change usually lasts about five to seven days from the initial application. Another sunless tanning product is a tanning pill that contains canthaxanthin, most commonly used as a color additive in certain foods (see plants and other organic molecules ). While the FDA has approved the use of canthaxanthin in food, it does not approve its use as a tanning agent. When used as a color additive, only very small amounts of canthaxanthin are necessary. As a tanning agent, however, much larger quantities are involved.

Upon taking the tanning pill, canthaxanthin is deposited all over your body, including in your skin, which turns an orange-brown color. Various side effects, including canthaxanthin retinopathy, a condition in which yellow deposits form in the retina of the eye, have been identified. Most tanning accelerators are lotions or pills that contain the amino acid tyrosine. The producers claim that the tyrosine stimulates and increases melanin formation, thereby accelerating the natural tanning process. However, more scientific data is needed to determine the validity of these claims and to assess the safety of using large amounts of tyrosine. Another popular form of sunless tanning is the bronzer. These powders and moisturizers, once applied, create a tan that can easily be removed with soap and water. More like make-up, these products tint or stain your skin only until they are washed off. Lightening dark skin While some light skinned people tan or use cosmetic means to darken their skin, dark-skinned people may use cosmetic means to lighten their skin. This is an even more controversial process than tanning, as the desire for whiter skin is intertwined with issues of health, self-image, racial inequalities and colonial attitudes.

The term skin whitening covers a variety of cosmetic methods used to lighten the skin’s color. Most skin-lightening treatments are aimed at inhibiting tyrosinase, to reduce or halt the production of melanin. Exfoliants such as topical cosmetics or chemical peels may be used, or the skin may be treated with lasers, depending on the response of the individual’s skin to treatment. As with some tanning products, there is some evidence suggesting that there are harmful side effects to skin-lightening products. Causes of Pigment & Color Changes in the Skin & Coat in Dogs Causes of Pigment & Color Changes in the Skin & Coat in Dogs Veterinary & Aquatic Services Department, Drs. Foster & Smith Email Article The skin and coat of a dog may sometimes change color or become lighter or darker. This may be a normal process, or may be due to a serious disease. If the skin or coat has a color other than white, it is said to be 'pigmented.' Colors include brown, black, red, purple, and yellow. If the skin is a darker color than normal, it is said to be 'hyperpigmented.' The table below provides a list of the majority of the conditions, which are associated with pigment change.

This extensive listing helps you understand why a quick diagnosis may be difficult to make and various diagnostic tests may need to be performed. The most common conditions causing pigment or color changes are color-coded gray in the table (some may be more common in certain geographical areas).

Condition Inherited form seen in Dachshunds; secondary form caused by friction, hormonal abnormalities, or hypersensitivities Darkening of the skin; in secondary form see scratching and hair loss History, physical exam; in secondary form, testing to determine underlying cause Primary: No treatment; Secondary: treat underlying disease; in some cases, steroids and Vitamin E supplementation Adrenal sex hormone responsive dermatosis More common in Pomeranians, Chows, Keeshonden, and Samoyeds Hair loss starts on neck, tail, and back of thighs and progresses to trunk; dog appears to have a 'puppy coat'; skin darkens Biopsy; eliminate other causes Apocrine sweat gland cyst Common Single, round, smooth nodules with no hair; may appear bluish; usually filled with a watery liquid; most common on head, neck, and limbs Physical exam; biopsy Basal cell tumors Cancerous , slow-growing tumor , which rarely metastasizes; seen in older dogs Single, sometimes fluid-filled nodules , which may ulcerate; usually on the head, neck, and chest; may be hyperpigmented Biopsy Black hair follicular dysplasia/ alopecia/ dystrophy Rare hereditary disease in dogs with hair of multiple colors; more common

 in Bearded Collies, Basset Hounds, Salukis, Beagles, Dachshunds, and Pointers Loss of dark or black hair only; symptoms appear between 3 and 6 weeks of age; sometimes scaling Clinical signs, biopsy Shampoos for scaling, if necessary Bowen's disease A rare type of squamous cell carcinoma in which multiple lesions develop Lesions start out as thickened, dark, raised, and well-delineated; progress to ulcers and crusts and bleed easily; lesions found on the head, neck, shoulder, forelegs, mouth, and genital areas Biopsy Lesions may come and go and are not always treated; some anti-cancer drugs and radiation have been tried with mixed results Bruises Generally the result of trauma; may indicate abnormally low platelets, clotting problems, or hormonal problems Areas of bluish-black discoloration of the skin Medical history very important; blood tests, if abnormality expected None, if the result of trauma; in other cases, treat underlying cause Castration responsive dermatosis More common in young unneutered dogs, and in Chows, Samoyeds, Keeshonden, Alaskan Malamutes, Miniature Poodles, and Pomeranians

 Symmetrical hair loss in genital area and neck; hair loss may progress onto trunk; skin may appear darker; severe scaling; hair color may fade; coat is similar to a 'puppy coat' Physical exam and history; eliminate other causes; blood tests for hormone levels Castration Chronic atopy, allergies, bacterial infections Darkening and sometimes thickening of the skin History, physical exam; blood tests to rule out other possible causes Treat/remove underlying cause Color dilution/mutant alopecia Hereditary condition affecting dogs with blue (diluted black) or fawn coat colors; more common in Dobermans, Dachshunds, Great Danes, Yorkshire Terriers, Whippets, and Greyhounds Hair in the blue- and fawn-colored areas starts to thin at around 6 months of age; secondary folliculitis often develops Breed, history, and coat color None; avoid excessive grooming or harsh shampoos; protect skin to prevent secondary bacterial infections Cushing's disease (hyperadrenocorticism) Caused by an increase in corticosteroids in the body - either due to increased production by the body or as a side effect of high doses or prolonged therapy with corticosteroids Hair loss, thinning of skin, hyperpig

mentation , easy bruising, seborrhea, comedones (black heads), may see calcinosis cutis; lethargy, increased thirst and urination, pot-bellied appearance Adrenal gland function tests, urinalysis, chemistry panel, CBC If due to glandular tumors , selegiline, o,p-DDD (Mitotane), or surgical removal of tumor; if due to high steroid doses, withdraw use of steroids slowly Cyclic (cicatrical) alopecia; seasonal flank alopecia Growth cycle of hair stops at certain times of the year Symmetrical hair loss with definite borders; usually on back and flanks; skin may become darker History, clinical signs, biopsy Demodectic mange (red mange, puppy mange) Infection with the Demodex mite - occurs when the immune system is deficient Hair loss, scaliness , redness, pustules , ulcers , sometimes itching, darkening of the skin Skin scraping and microscopic examination NO Steroids Rare cancer of T lymphocytes seen in older dogs Can take multiple forms: redness with itching and scale ; ulcers and loss of pigment; one or more nodules; oral ulcers Needle or other biopsy Poor response to treatments, which include chemotherapy , surgical

 removal, retinoids, fatty acids Estrogen responsive dermatosis (ovarian imbalance type II) More common in young spayed dogs, and in Dachshunds and Boxers Hair loss starting at the genital area and flanks and moving forward; hair color may fade; coat is similar to a 'puppy coat' Physical exam and history; eliminate other causes; response to therapy Estrogen replacement therapy; caution - can have severe side effects Follicular cyst Most common cyst ; may be called 'sebaceous cysts' by some veterinarians Single round nodules on or underneath the skin; may appear bluish; may contain a thick, yellowish to gray material; usually found on the head, neck, and trunk Biopsy Surgical removal optional; do NOT squeeze these cysts, since a severe skin reaction will occur Follicular dysplasia (non-color linked) Patchy hair loss of unknown cause seen in the Siberian Husky, Doberman Pinscher, Airedale, Boxer, Staffordshire Bull Terrier, Curly Coated Retriever, Irish Water Spaniel, and Portuguese Water Dog In Huskies, hair loss on the body, reddish tinge to hair; in Dobermans, hair loss over lum

bar area; in Boxers and Terriers, hair loss over lumbar area, skin may be hyperpigmented ; in Retrievers and Spaniels, loss of guard hairs on back and trunk and secondary hairs are dull and lighter in color; Breed, biopsy None Growth hormone responsive alopecia Not well understood; thought to be caused by an enzyme deficiency or decrease of adrenal hormones , which allows certain other hormones to accumulate in the body: more common in Pomeranians, Chow Chows, Keeshonden, Samoyeds, and Poodles Hair loss on neck, tail, and the back of the thighs; skin darkens; usually starts when dog is less than two years old Hormonal blood testing Malignant , invasive tumor more common on sun-damaged skin Blue to reddish black nodule ; usually on chest or abdomen; often ulcerate Biopsy Surgical removal; need to remove large area around the tumor; if tumor is on a leg, amputation of the leg is commonly recommended Hyperestrogenism (ovarian imbalance type I) Rare disease in which female animals have excess levels of estrogen; can be caused by cancer of the ovaries Symmetrical loss of hair; hair pulls out easily; darkening of the skin; enlarged nipples and vulva

; may rarely see seborrhea and itching History, physical exam, rule out other causes of hair loss, measure blood estrogen levels Spay; look for metastasis to the lungs Hypothyroidism Decreased production of thyroid hormone ; most common hormonal disease affecting the skin in dogs Hair loss, dry and brittle hair, seborrhea; secondary bacterial and yeast infections; lethargy, obesity, slow heart rate; changes in skin pigmentation may occur Thyroid gland function tests, chemistry panel, CBC Lifetime thyroid supplementation Injection site alopecia Hair loss at the site of an injection of a medication or vaccine; skin may become thickened; in cats, ulcers may develop Hair loss occurs several months after injection; area may become hyperpigmented History and physical examination None; the condition is permanent Interstitial cell tumor Tumor of the testicle; may not cause any skin changes If skin changes occur, See Seborrhea, loss of hair on the trunk, enlargement of the tail gland and perianal glands; may see increased pigment in the skin Biopsy Generally results from liver disease Yellowing of the skin, mucous membranes, and whites of the eyes Physical exam; blood tests to assess liver function Treatment of underlying liver disease Lentigo Circular brownish-black

 areas of coloration Physical exam; skin biopsy to rule out other causes of hyperpigmentation None Usually follows some other underlying disease Itching, redness, hair loss, greasy scales ; if chronic, develop hyperpigmentation Skin scraping/smear and microscopic examination, culture Treat underlying disease; oral ketoconazole; miconazole shampoos Common cancer which is graded from 1-4: Grade 1 is slow-growing tumors , and Grade 4 is rapidly growing malignant tumors with metastases Tumors may be of various sizes, appearances, and numbers Biopsy to grade the tumors, which determines treatment and prognosis Depends upon grade; surgical removal, taking large area around tumor; chemotherapy; prednisone; radiation Melanoma Malignant tumor of older dogs Usually single dark-colored nodule , which often ulcerates Biopsy Surgical removal, taking large area around tumor Nasal depigmentation (Dudley nose) Previous black nose turns chocolate brown to light pink; more common in Yellow Labs, Golden Retrievers, Poodles, and Dobermans; not associated with a disease process Progressive fading of color of nose with no other signs such as crusting or ulceration Physical exam None Pemphigus foliaceus The most common form of pem

phigus in the dog; an autoimmune disease; some breeds are at increased risk Often affects feet and head; starts with pustules and progresses to severe crusting ; depigmentation of the nose is common; itching may occur; if footpads and nails affected often see lameness; symptoms wax and wane; severely affected animals may have fever and loss of appetite History, physical exam, skin scraping, and biopsy Corticosteroids, other immunosuppressive therapy, gold injections Red/brown staining of hair Often caused by body secretions such as tears and saliva from licking Light colored hair turns a reddish brown Clinical signs, history Rocky mountain spotted fever Caused by an organism spread by ticks; skin lesions are not always present Fever, loss of appetite, depression, pain in joints, edema, hemorrhages under the skin (appear as bruises), ulceration of mucous membranes and extremities Special blood tests to detect the organism or antibodies to it; biopsy Antibiotics and supportive care Sertoli cell tumor Tumor of the testicles in middle-aged dogs Male dogs take on female sexual characteristics; hair loss, increased skin pigment, reddened area on prepuce Physical exam Nerve regrowth after tail docking causes symptoms Nodule at site of docking

, itching with self-mutilation, hair loss, and hyperpigmentation History and symptoms Surgical removal Tail gland hyperplasia Dogs have a sebaceous gland on the top of the tail near its base; in this disorder, the gland enlarges; seen in unneutered dogs and secondary to other diseases such as hypothyroidism Oily area, hair loss, crusts , and hyperpigmentation on area over gland Clinical signs; look for underlying cause Castration may help; treat underlying cause; surgical removal Uveodermatologic syndrome Hypersensitivity to melanin (the dark pigment) in the skin and eyes Pigment loss on nose, lips, and eyelids; occasionally footpads, scrotum, and anus can be affected; rarely see ulcers or drainage; uveitis (inflammation of the eye) may occur History, clinical signs, biopsy Long-term prednisone, azathiprine; appropriate eye medications Vitiligo (Decreased Pigment) Can be hereditary or caused by an autoimmune reaction Loss of pigment, which may be temporary or permanent; usually on nose, lips, and face Clinical signs, skin biopsy

Question: What is the pigment that colors skin?
Answer: Melanin