There are several types of dermatitis, including:

• Contact dermatitis, a rash that results from either repeated contact with irritants or contact with allergy-producing substances, such as poison ivy
• Neurodermatitis, a chronic itchy skin condition localized to certain areas of the skin
• Seborrheic dermatitis, a common scalp condition that often causes dandruff
• Stasis dermatitis, a skin condition that's caused by a buildup of fluid under the skin of the legs
• Atopic dermatitis, more commonly known as eczema or atopic eczema, a chronic itchy rash that tends to come and go
• Perioral dermatitis, a bumpy rash around the mouth

Each has distinct signs and symptoms. Common signs and symptoms include:

• Redness
• Swelling
• Itching
• Skin lesions

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

A number of health conditions, allergies, genetic factors, physical and mental stressors, and irritants can cause dermatitis:

• Contact dermatitis results from direct contact with one of many irritants or allergens. Common irritants include laundry soap, skin soaps or detergents, and cleaning products. Possible allergens include rubber; metals, such as nickel; jewelry; perfume; cosmetics; weeds, such as poison ivy; and neomycin, a common ingredient in topical antibiotic creams.

  It takes a greater amount of contact with an irritant over a longer time to cause dermatitis than it takes for an allergen. If you're sensitized to an allergen, just brief exposure to a small amount of it can cause dermatitis. Once you develop sensitivity to an allergen, you typically have it for life.

• Neurodermatitis typically develops when something has created an itchy sensation in a specific area of your skin. This irritation may lead you to rub or scratch your skin repeatedly in that area. Common locations include ankles, wrist, outer forearm or arm, and the back of your neck. Neurodermatitis may also be associated with other skin conditions, such as dry skin, eczema or psoriasis. Contact dermatitis caused by allergens doesn't seem to be a factor, though.
• Seborrheic dermatitis causes a red rash with yellowish and somewhat "oily" scales, usually on the scalp. It's common in people with oily skin or hair, and it may come and go depending on the season of the year. It may occur during times of physical stress, travel or in people who have neurological conditions, such as Parkinson's disease. In infants, this disorder is known as cradle cap.
• Stasis dermatitis can occur when fluid accumulates in the tissues just beneath your skin, and typically involves the lower leg. The extra fluid interferes with your blood's ability to nourish your skin and places extra pressure against your skin from underneath. Varicose veins and other chronic conditions that affect circulation in your legs often cause this fluid buildup.

• Atopic dermatitis often occurs with allergies and frequently runs in families in which members have asthma or hay fever. It usually begins in infancy and may vary in severity during childhood and adolescence. It tends to become less of a problem in adulthood, unless you're exposed to allergens or irritants in the workplace.

  The exact cause of this disorder is unknown, but is likely due to a combination of dry, irritable skin together with a malfunction in the body's immune system. Stress can exacerbate atopic dermatitis, but it doesn't cause it.

• Perioral dermatitis may be a form of the skin disorder rosacea, adult acne or seborrheic dermatitis, involving the skin around the mouth or nose. The exact cause is unknown, but makeup, moisturizers, topical corticosteroids or some dental products containing fluoride may play a role.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

See your doctor if:

• You're so uncomfortable that you're losing sleep or are distracted from your daily routines
• Your skin becomes painful
• You suspect your skin is infected
• You've tried self-care steps without success

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

Your doctor may diagnose dermatitis after talking to you about your signs and symptoms and examining your skin.

Patch testing
In the case of contact dermatitis, your doctor may conduct patch testing on your skin to see which substances inflame your skin. In this test, your doctor applies small amounts of various substances to your skin under an adhesive covering. During return visits, your doctor examines your skin to see if you've had a reaction to any of the substances.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

• Impetigo. The open sores and fissures that can occur with dermatitis may become infected. A mild form of infection is impetigo, usually due to staphylococci bacteria. Having atopic dermatitis predisposes you to this infection.
• Cellulitis. If you notice red streaks on your skin, you may have cellulitis, a bacterial infection of tissues under the skin. Cellulitis appears as intensely inflamed skin that's swollen, red, tender and warm to the touch, with spreading, indistinct margins. Cellulitis that occurs in someone whose immune system is compromised is potentially life-threatening. See your doctor as soon as possible if you think you have cellulitis.

Scarring and changes in skin color are other potential complications from dermatitis.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

Dermatitis treatment varies, depending on the cause:

• Contact dermatitis. Treatment consists primarily of identifying the cause of the rash and then avoiding it. Sometimes, creams containing hydrocortisone or other stronger steroidal creams with or without wet dressings may help relieve redness and itching. It can take as long as two to four weeks for this type of dermatitis to clear up.
• Neurodermatitis. Getting you to stop scratching and to avoid further aggravating your skin are the treatment objectives. Accomplishing this may mean covering the affected area to prevent you from scratching it. Hydrocortisone and similar lotions and creams may help soothe your skin. You also may find that wet compresses provide relief. Antidepressants or anti-anxiety medications are helpful for some people. Also, counseling can help you learn how your emotions and behaviors can fuel — or prevent — itching and scratching.
• Seborrheic dermatitis. Medicated shampoos are usually the first treatment choice. Commonly used shampoos contain tar, pyrithione zinc, salicylic acid or ketoconazole as the active ingredient. Hydrocortisone creams and lotions may soothe nonscalp seborrheic dermatitis. If you develop a secondary infection, you may need treatment for this, too.
• Stasis dermatitis. Treatment consists of correcting the condition that causes fluid to accumulate in your legs or ankles for extended periods. This may mean wearing elastic support hose or even having varicose vein surgery. You may also use wet dressings to soften the thickened yet fragile skin and to control infection.
• Atopic dermatitis. Treatment typically consists of applying hydrocortisone-containing lotions to ease signs and symptoms. If your skin cracks open, your doctor may prescribe wet dressings with mildly astringent properties to contract your skin, reduce secretions and prevent infection. If itching is severe, your doctor may suggest you take antihistamines. Light therapy, which involves exposing your skin to controlled amounts of natural or artificial light, also may help prevent recurrences.
• Perioral dermatitis. Treatment for this condition is usually with the oral antibiotic tetracycline. You may need to continue this treatment for several months to prevent a recurrence. Your doctor may prescribe a very mild corticosteroid cream in the initial phase of treatment to reduce signs and symptoms of perioral dermatitis. When stronger corticosteroids are used, the condition may return temporarily and even worsen when the medication is stopped.

For all types of dermatitis, occasional use of over-the-counter antihistamines can reduce itching.

Immunomodulators
A class of nonsteroidal medications called immunomodulators, such as tacrolimus (Protopic) and pimecrolimus (Elidel), may help treat seborrheic dermatitis and atopic dermatitis. These medications affect the immune system and have anti-inflammatory and mild antifungal properties.

Due to possible concerns about the effect of prolonged use of these medications on the immune system, the Food and Drug Administration recommends that Elidel and Protopic be used only when other treatments have failed, or if someone can't tolerate other treatments.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

Preventing contact dermatitis means avoiding coming into contact with those substances, such as poison ivy or harsh soaps, that may cause it.

Try to identify and avoid triggers that worsen the inflammation. Rapid changes of temperature, sweating and stress can worsen some forms of dermatitis. Avoid direct contact with wool products, such as rugs, bedding and clothes, as well as harsh soaps and detergents.

Avoiding dry skin may be one factor in helping you prevent future bouts of dermatitis. These tips can help you minimize the drying effects of bathing on your skin:

• Bathe less frequently. Most people who are prone to dermatitis don't need to bathe daily. Try going a day or two without a shower or bath. When you do bathe, limit yourself to 15 to 20 minutes, and use warm, rather than hot, water.
• Use only mild soaps. Choose soaps, such as Basis, Dove or Olay, that clean without excessively removing natural oils. Deodorant and antibacterial soaps may be more drying to your skin. Use soap only on your face, underarms, genital areas, hands and feet. Use clear water elsewhere.
• Dry yourself carefully. Brush your skin rapidly with the palms of your hands, or gently pat your skin dry with a towel after bathing.
• Moisturize your skin. Seal in moisture, while your skin is still damp, with an oil or cream. Pay special attention to your legs, arms, back and the sides of your body. If your skin is already dry, consider using a lubricating cream made for dry skin, such as Eucerin.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

These steps can help you manage dermatitis:

• Apply an anti-itch cream or calamine lotion to the affected area. A nonprescription hydrocortisone cream, containing at least 1 percent hydrocortisone, can temporarily relieve your itch. A nonprescription oral antihistamine, such as diphenhydramine (Benadryl, others), may be helpful if your itching is severe.
• Apply cool, wet compresses. Covering the affected area with bandages and dressings can help protect your skin and prevent scratching.
• Take a comfortably cool bath. Sprinkle your bath water with baking soda, uncooked oatmeal or colloidal oatmeal — a finely ground oatmeal that is made for the bathtub (Aveeno, others).
• Avoid scratching whenever possible. Cover the itchy area with a dressing, if you can't keep from scratching it. Trim nails and wear gloves at night.
• Wear smooth-textured cotton clothing. This will help you avoid irritating the affected area.
• Use a mild, unscented laundry detergent when washing clothes, towels and bedding. Try using the extra rinse cycle on your wash machine.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.