Slide show: Common skin rashes

Pityriasis rosea

Pityriasis rosea is a fine, itchy, scaly or bumpy rash that usually appears first as a single patch (A) anywhere on the body. This rash (herald patch) goes away. Then several days to a few weeks later, another rash breaks out over the back or chest in a pattern that resembles drooping branches of a pine tree (B).

The rash persists for several weeks and heals without scarring. Medicated lotions may lessen itchiness and speed the disappearance of the rash. Often, though, no treatment is required. The condition is not contagious and seldom recurs.

Contact dermatitis

Contact dermatitis is a rash caused by direct contact with certain substances. Or it can be caused by an allergic reaction to certain substances. Irritant contact dermatitis (A) usually produces a dry, scaly, itchy rash. Many substances, such as cleaning products or industrial chemicals, cause this condition.

Allergic contact dermatitis (B) produces a very itchy rash with bumps, swelling and sometimes blisters, as with this case of poison ivy. Common allergy-causing agents (allergens) are latex rubber, nickel and poison ivy. Allergic contact dermatitis develops after an initial exposure to the allergen.

To treat your rash, try to figure out what caused it and avoid that substance. You can also apply medicated cream to ease the discomfort of your symptoms.

Drug rash

A rash may occur as a side effect of taking a drug or as an allergic reaction to it. A drug rash might be caused by antibiotics, water pills (diuretics) or many other medications.

A drug rash might show up within an hour of taking a new medication. Or it might appear in a few days. The rash often begins as spots that range in color from pink to purple. The color of the spots depends on your skin color. The spots spread and merge. If you stop taking the drug that caused the rash, it will usually clear up in days to weeks.

Rarely, a drug rash is part of a more serious, potentially life-threatening allergic reaction that affects breathing (anaphylaxis). These severe reactions require emergency care.

Heat rash (miliaria)

Heat rash (miliaria) occurs when the flow of sweat is obstructed, usually due to hot, humid weather or overdressing.

Prickly heat (miliaria rubra) (A) is a type of heat rash that appears as clusters of small bumps that produce a pricking or stinging sensation. The bumps range in color from red on white skin to gray or white on brown and Black skin. Miliaria crystalline (B), another type of heat rash, appears as clear, fluid-filled bumps.

Heat rash isn't serious and usually resolves when the affected skin cools. Cool compresses or a cool bath might help. You can prevent heat rash by wearing loose, lightweight clothing and avoiding excessive heat and humidity.

Intertrigo

Intertrigo (in-tur-TRY-go) is inflammation caused by skin-to-skin friction, most often in warm, moist areas of the body, such as the groin, between folds of skin on the abdomen, under the breasts, under the arms or between the toes. The affected skin may be sensitive or painful, and severe cases can result in oozing sores, cracked skin or bleeding.

Intertrigo usually clears up if the affected areas are kept as clean and dry as possible. Try wearing loose clothing and reducing skin-to-skin friction in affected areas. Applying an ointment (Vaseline, A+D, others) to the skin can help. Weight loss may be helpful as well.

Sometimes, a bacterial or fungal infection can develop at the site of intertrigo. If this happens, you may need a medication to heal your skin.

Lichen planus

Lichen planus (LIE-kun PLAY-nus) is an inflammatory condition that can affect the skin and mucous membranes. On the skin it causes itchy, flat-topped bumps (lesions). The bumps may be red, purple, ashy or brown depending on skin color. In the mouth, vagina and other areas covered by a mucous membrane, lichen planus forms lacy discolored patches.

The condition may develop gradually over several weeks. After that, it may persist for months or years. The affected skin often heals with patches of darker skin (postinflammatory hyperpigmentation), especially in people with brown or Black skin.

The symptoms of mild lichen planus on the skin can be eased by applying cool compresses or a nonprescription hydrocortisone cream. Severe symptoms may require treatment with a prescription drug.

Lesions on mucous membranes tend to take longer to heal and often recur.

Psoriasis

Psoriasis (suh-RIE-uh-sis) is the rapid buildup of rough, scaly skin. The extra skin cells form thick, gray or silvery scales, and itchy sometimes painful patches. Psoriasis often occurs on the lower back, soles of the feet, knee, face, elbows (A) or scalp (B). The rash might be red or purple, which might be difficult to see on Black or brown skin.

The condition tends to flare up periodically. Common triggers in people with a genetic predisposition to psoriasis include infections, cuts or burns, certain medications, and stress.

For some people, psoriasis is a mild nuisance. For others, it can be disabling, affecting large areas of skin for a long time. Signs and symptoms might be eased by moisturizing, avoiding triggers, and seeking medical treatment, such as prescription creams and light therapy.

Ringworm of the body (tinea corporis)

Ringworm of the body (tinea corporis) is a fungal infection that can cause an itchy, circular rash. Ringworm gets its name because of its ring shape — there is no worm under the skin. The ring grows outward as the infection spreads, sometimes developing as overlapping circles or in separate areas of the body or in a pattern that's not ring-shaped at all.

Ringworm often spreads by direct skin-to-skin contact with an infected person or animal. Mild ringworm often responds to antifungal medications applied to the skin.

Rosacea

Rosacea (roe-ZAY-she-uh) is a long-term (chronic) skin condition of adults that causes facial flushing. Eventually it can lead to persistent flushing in the face and tiny broken blood vessels on the nose and cheeks. Some people also develop small, acne-like bumps on the nose, cheeks, forehead and chin.

Most people with rosacea experience occasional flare-ups, usually in response to factors that increase blood flow to the surface of the skin. Triggers vary from person to person. Common triggers are spicy foods, hot drinks, exercise, cosmetics, extreme temperatures, alcoholic beverages, emotional stress, wind and sunlight.

Rosacea has no cure, but treatments may control or reduce your signs and symptoms. It also helps to identify what causes flare-ups and avoid those triggers.

Shingles (herpes zoster)

Shingles (herpes zoster) is a painful rash caused by the varicella-zoster virus — the same virus that causes chickenpox. After you've had chickenpox, the virus remains inactive in nerve tissue. Years later, the virus may reactivate as shingles.

A shingles outbreak may start with pain with no obvious external cause. Within several days, clusters of fluid-filled blisters appear in an area on one side of the body. The blisters then break open and crust over. Within about three weeks, the crusts fall off. Pain and itching after the rash clears up (postherpetic neuralgia) may persist for months or years.

Early treatment can help shorten a shingles infection and lessen the chance of postherpetic neuralgia. If you're over age 50, talk with your doctor about shingles vaccine options.

Swimmer's itch (cercarial dermatitis)

Swimmer's itch (cercarial dermatitis) is a burning or itchy rash caused by an allergic reaction to waterborne parasites that burrow into the top layer of skin. The parasites soon die, but you're temporarily left with tiny bumps or blisters.

Swimmer's itch isn't serious and usually clears up on its own in 7 to 10 days. At-home remedies — soothing lotions, lukewarm baths with Epsom salts or baking soda — may ease the itchiness. You might also control the symptoms with antihistamines or anti-itch creams.