What Is It?
Eczema is the most common type of dermatitis (inflammation of the skin). Eczema refers to several conditions that share a pattern of changes in the surface of the skin. Eczema first appears as an episode of itching, redness and tiny bumps or blisters. When it develops into a long-term condition (chronic eczema), it leads to skin thickening, scaling, flaking, dryness and color changes. There are many types of eczema, depending on the cause and the shape and location of the rash. Most are related to allergies or to contact with irritating chemicals. Some are associated with underlying medical conditions that cause fluid retention in the legs. In the United States, eczema affects approximately 10 percent of the population.
- Atopic eczema (atopic dermatitis) — This type of eczema comes and goes repeatedly, and usually occurs in people who have a genetic (inherited) tendency to have allergies. In about 70 percent of cases, either the patient or a family member has allergic asthma, hay fever or food allergies. Atopic eczema appears early in life, usually in babies between 2 months and 18 months old. In babies, atopic eczema primarily affects the face, neck, ears and torso. It also appears on the tops of feet or the outside surface of elbows. Atopic eczema also is seen in older children, teen-agers and adults, where it usually involves the skin inside the creases of the inward bend of the elbow, knee, ankle, or wrist joints, the hands, or the upper eyelids.
- Contact dermatitis — When irritants touch the skin, they can produce two types of contact dermatitis. Irritant contact dermatitis is direct irritation of the skin. The problem is called allergic contact dermatitis when an allergic reaction occurs in the skin. Irritant contact dermatitis can be caused by prolonged contact with mild irritants such as bubble bath, soap, sweat, saliva, urine and even water. Allergic contact dermatitis only occurs in people who have an allergy to a specific substance. Each year, about 70 percent of people in the United States are affected by some type of skin allergy. The most common allergens are poison ivy, poison oak and poison sumac. Other common substances that trigger skin allergies include construction materials used to build homes and offices, cleaning products, deodorants, cosmetics and medications. Dermatitis of the earlobes can be caused by an allergy to earrings that contain nickel. Chemicals in fragrances, skin cream and lotions, shampoos and shoes or clothing also can cause allergic reactions.
- Hand eczema — This form of chronic eczema is limited to the hands. It can be related to atopic eczema or it can occur because of repeated hand washing or exposure to strong detergents. Occasionally, hand eczema is caused by an allergy, such as a latex allergy.
- Nummular eczema — This type of eczema causes round, coin-sized patches of irritated skin, typically on the legs, arms or chest. It usually occurs in adults. It can be related to atopic dermatitis and, less often, allergic contact dermatitis. In a few cases, it represents an allergic reaction to a fungal infection such as athlete’s foot. In this case, nummular eczema still appears typically on arms, legs or chest, even if the fungal infection is elsewhere on the body.
- Asteatotic eczema — This dry-skin eczema causes fine cracks in the skin, usually first involving the lower legs, where there are fewer oil glands. It commonly occurs in the elderly, especially during winter months spent indoors in a low-humidity environment.
- Stasis dermatitis — This type of eczema occurs on the calves, ankles and feet in people who have varicose veins or other conditions that lead to poor blood circulation in the lower legs. Leg swelling leads to itching, fine red bumps, skin darkening and, sometimes, ankle sores.
- Lichen simplex chronicus — This form of eczema is a reaction to repeatedly scratching or rubbing the skin in one location. A nervous skin-scratching habit can lead to thickened, discolored skin on the wrist, the ankle, groin or the back of the neck. Skin picking can lead to smaller bump-like areas of the same type of rash called prurigo nodularis.
- Seborrheic dermatitis (seborrhea) — Some doctors consider seborrhea to be a type of eczema, although it creates a greasier rash than is usual for eczema conditions. This scaly dermatitis commonly appears on the scalp as “cradle cap” in infants or dandruff in adults. It commonly affects the face or neck around the nose and at the scalp line. It probably is triggered by the skin fungus Pityrosporum ovale.
Short-term symptoms of eczema include skin itching, redness and tiny bumps or blisters. If these symptoms remain untreated, the skin can become thick, scaly and dry, with areas of hair loss and color changes. Skin affected by long-term eczema also is more vulnerable to secondary infections, usually caused by bacteria.
Each type of eczema also has specific characteristics and pattern of symptoms:
- Atopic eczema (atopic dermatitis) — Atopic dermatitis appears as wet (weeping) or crusted patches that are very itchy and irritated. Scratching the itchy patches causes more irritation and increases the risk of infection by bacteria.
- Contact dermatitis — When an irritant causes contact dermatitis, symptoms can range from a mild redness to severe skin blistering or ulceration. When contact dermatitis is triggered by an allergic reaction, it usually causes skin redness, fine red bumps or blisters and severe itching. In contact dermatitis caused by plant allergies (poison ivy, poison oak, poison sumac), the reaction usually is intense, with bumps and blisters occurring in lines or streaks where the leaves of the plant brushed against the skin.
- Hand eczema — Irritant hand eczema usually appears during the winter as areas of dry, cracked skin, with or without redness. Other forms of hand eczema generally cause itching and pinpoint, red bumps or blisters and scaling. If you wear rings, skin under the rings can be affected first.
- Nummular eczema — Nummular eczema begins as small areas of irritation that turn into round red, crusted or scaly patches.
- Asteatotic eczema — Asteatotic eczema usually occurs on the lower legs and causes itching or stinging pain in areas of dry, cracked, reddened skin, with or without tiny bumps.
- Stasis dermatitis — Stasis dermatitis usually begins with mild redness and itching of the lower legs, which are already slightly puffy or very swollen as a result of poor circulation in the legs. The poor circulation usually is caused by varicose veins or poorly functioning veins, but it can be caused by leg swelling (edema) related to heart failure or kidney problems. If redness and tenderness develop suddenly, it could be caused by a secondary bacterial infection. Bacterial infections require immediate medical attention.
- Lichen simplex chronicus — This rash creates thickened, leathery skin with darkening of skin color. It is very itchy, but scratching makes the problem worse.
- Seborrheic dermatitis (seborrhea) — Seborrheic dermatitis causes red, scaly patches with yellow, greasy crusts. These appear most commonly on the scalp as dandruff, but also can occur elsewhere on the body, including the eyebrows, eyelids, ears and skin creases near the mouth and nose. These patches can be itchy or can cause burning. The scalp lesions in infants (cradle cap) can appear yellowish and greasy and usually cause no discomfort.
Depending on your pattern of skin symptoms, your doctor will ask about your personal and family allergy history, your history of exposure to irritating chemicals and your contact with potential allergy triggers, such as poison ivy.
In many cases, your doctor can diagnose eczema by examining the skin. If your doctor suspects that allergies are involved, patch testing with various allergenic chemicals (nickel, lanolin, fragrances, etc.) may be necessary.
Depending on the type of eczema, symptoms may go away after a week or two, or persist for years. For example, contact dermatitis caused by poison ivy usually lasts for about two weeks, while atopic dermatitis which began in childhood can persist into adulthood. Stasis dermatitis related to varicose veins can last for many years.
In general, you can help to prevent eczema flare-ups by avoiding exposure to extreme temperatures, dry air, harsh soaps and bubble baths. Also, try using blankets and clothing made of cotton instead of more irritating fabrics such as wool or stiff synthetics, such as polyester. After showering or bathing, pat dry so you leave a little moisture on your skin and apply a moisturizing cream or lotion to trap moisture in the skin. Use a room humidifier to add moisture to indoor air during the winter heating season.
To help to prevent contact dermatitis, avoid skin contact with irritating chemicals, plants, jewelry and substances that trigger skin allergies. If you have severe varicose veins, you can help prevent stasis dermatitis by wearing compression stockings and by elevating your legs if you sit for long periods. Be alert for any reactions within 48 hours of using a medication. Antibiotics applied to the skin and taken by mouth both can trigger a skin reaction such as hives or more sensitive skin. If this happens, call your doctor to get a substitute medication.
Your doctor usually will review your skin-care routine first to make sure you are doing everything possible to prevent symptoms. If, despite these measures, your eczema is bothersome, he or she might prescribe a corticosteroid ointment or cream for you to use on the affected area. In atopic dermatitis, mild- or medium-strength topical (applied to the skin) steroids generally are used, while the strongest steroids may be needed to treat allergic contact dermatitis. To relieve severe itching, your doctor may prescribe an antihistamine. If there are signs of bacterial skin infection, antibiotics usually are needed.
Sometimes, in very severe cases of eczema, your doctor will prescribe a short course of oral steroids or stronger medications that decrease the activity of the immune system. However, steroids taken for prolonged periods and other drugs that suppress the immune system can have serious side effects and must be used cautiously. In some patients, treatment with ultraviolet (UV) light is another option.
Seborrhea in adults is best treated with dandruff shampoo, and, occasionally, with prescription antifungal facial creams or rinses. Cradle cap in infants eventually will clear up without treatment, though it can last for several months. The crust usually can be loosened by applying baby oil to the scalp for 30 to 60 minutes before brushing with a soft brush and then washing with baby shampoo.
When treating a contact allergy in a child, avoid topical preparations that contain an antihistamine (such as calamine lotion with diphenhydramine) because too much antihistamine can be absorbed through the skin. Some children also have a skin reaction to these preparations.
When To Call A Professional
Your doctor usually can help whenever you have an area of skin that is red and very itchy, or skin that is cracked, blistered or painfully dry. You should ask your doctor for an urgent evaluation if you have signs of infection — an area of skin that is painful, has yellow drainage or has streaking or spreading redness.
The prognosis varies from patient to patient, depending on the type of eczema and its response to treatment. For example, while most contact dermatitis heals within two to three weeks, most stasis dermatitis is a long-term problem that lasts for years. Among children affected by atopic eczema, about half still will have the problem as adults.
Diseases and Conditions Center
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.