Slide show: Types of dermatitis

Dermatitis — an inflammation of the skin — usually appears as swollen, red and itchy skin. It has many causes and occurs in many forms, including contact dermatitis and atopic dermatitis. Dermatitis isn't life-threatening or contagious, but it can be uncomfortable or even painful.

Depending on the type, dermatitis may clear within a few weeks without treatment, or it may require medical attention and a long-term treatment program.

Allergic contact dermatitis produces a red itchy rash, bumps and sometimes blisters. Common allergens include rubber, costume jewelry, perfume, cosmetics, hair dyes, weeds, such as poison ivy, and metals, such as nickel.

If you can identify and avoid the offending agent, the inflammation resolves without treatment in two to three weeks. See your doctor if your symptoms continue beyond that time frame or if the rash is uncomfortable or painful.

This form of dermatitis, commonly referred to as eczema, is a chronic condition that causes itchy, inflamed skin. Most often, it occurs in the folds of the elbows, backs of the knees or the front of the neck. It tends to flare periodically and then subside for a time, even up to several years. The exact cause of this skin disorder is unknown, but it may result from a malfunction in the body's immune system.

Even mild cases of atopic dermatitis can be extremely itchy. Self-care measures, such as avoiding soaps or other irritants and applying creams or ointments, help. See your doctor if your symptoms distract you from your daily routines or prevent you from sleeping.

Contact with an irritant causes this form of dermatitis. Irritant contact dermatitis produces red, dry itchy patches, which often resemble a burn. Frequently affecting the hands, fingers and face, irritant contact dermatitis usually occurs after repeated contact with the irritant. Common irritants include soap, detergents and skin-cleaning products.

If you can identify and avoid the substance, the rash usually resolves without treatment in two to three weeks. See your doctor if your symptoms continue beyond that time frame or if the rash is uncomfortable or painful.

Neurodermatitis, also known as lichen simplex chronicus, occurs because of repeated scratching. Chronic scratching can cause patches of thickened, brownish skin. These patches have definite margins that are thick and leather-like (lichenified). Typically, neurodermatitis occurs on the scalp, neck, wrist, upper forearm and ankle.

Treatment of neurodermatitis is difficult. It takes many weeks to months for the skin to return to normal. Successful treatment includes identifying and eliminating factors that may be aggravating the problem. Treatment may also include prescription-strength corticosteroid creams.

Perioral dermatitis usually affects the area around the mouth, causing small red bumps, pus-filled bumps or mild peeling. Sometimes the areas around the nose, cheeks and eyes are affected, too. The exact cause of perioral dermatitis is unknown, but makeup, moisturizers, topical corticosteroids or some dental products containing fluoride may play a role.

Treatment may include prescription-strength anti-acne medications. Discontinuing the use of strong corticosteroid creams, irritating skin products and cosmetics also may be beneficial.

Seborrheic dermatitis is characterized by greasy, scaly, itchy, red skin. It's often found on oily areas of the body, such as the face, upper chest and back. Seborrheic dermatitis can also appear on the scalp as stubborn, itchy dandruff. For infants, it's known as cradle cap.

Self-care measures, such as using over-the-counter medicated shampoos or hydrocortisone cream and washing frequently, help lessen the problem. See your doctor if these treatments don't work.

Stasis dermatitis occurs when varicose veins or other circulatory conditions cause fluids to build up in the lower legs. The swelling produces pressure beneath the skin and prevents adequate blood and oxygen from reaching the skin. This causes the skin at your ankles and shins to become discolored (red or brown), thick and itchy. Open sores or ulcers also may develop.

Treatment of stasis dermatitis consists of correcting the condition that causes the fluid to accumulate in your lower legs. In the case of varicose veins, surgery or other therapies, such as vein sclerosis, may be recommended.