James C Shaw, MD
UpToDate performs a continuous review of over 375 journals and other resources. Updates are added as important new information is published. The literature review for version 15.2 is current through April 2007; this topic was last changed on September 13, 2006. The next version of UpToDate (15.3) will be released in October 2007.
INTRODUCTION — Dermatitis is defined as an inflammation of the skin. The terms dermatitis include a wide variety of skin disorders, including atopic dermatitis (eczema), seborrheic dermatitis, contact dermatitis, latex dermatitis and allergy, and dyshidrotic dermatitis.
Depending upon the underlying cause, dermatitis can be a short-term or lifelong condition. In most cases, self-care measures and drug therapy can control the symptoms and prevent complications.
ATOPIC DERMATITIS (ECZEMA) — About 8 to 25 percent of people worldwide have atopic dermatitis (eczema). It often occurs in people who have other allergic disorders, such as asthma and allergic rhinitis (nasal inflammation caused by allergies, also known as hay fever). Family members are often affected.
Cause — The cause of eczema is unknown, but hereditary factors appear to play a strong role. The skin inflammation of atopic dermatitis results from an abnormal immune reaction that is triggered or worsened by exposure to allergens (substances that provoke an allergic reaction). About 85 percent of people with eczema have antibodies (proteins formed by the immune system) to foods or airborne allergens, such as dust mites and animal dander.
In children, eczema is often linked to food allergies. Common food allergens include milk, egg whites, wheat, corn, soybeans, and peanuts.
Symptoms — Most people with eczema develop their first symptoms before age five. Intense itching of the skin, redness, small bumps, and skin flaking are common (show picture 1). Scratching can cause additional skin inflammation, which can further worsen the itching. The itchiness may be more noticeable at nighttime. The skin is often dry, increasing the risk of skin injury with scratching. The skin lesions are therefore at risk for developing infection. Features of infection include pus-containing bumps in inflamed areas; prompt evaluation by a healthcare provider is recommended if this occurs
Features of eczema vary from one individual to another, and can change over time. Other features can include: Lichenification - Thick, leathery skin (usually as a result of frequent scratching) Icthyosis - Dry scales (show picture 2) Keratosis pilaris - Plugged hair follicles resulting in the development of small bumps, usually on the face, upper arms, and thighs Cheilitis - Inflammation around the lips Hyperlinear palms - Increased skin creasing on the palms Dennie-Morgan line - An extra fold of skin under the eye Periorbital darkening - Darkening of the skin around the eyes
Although eczema is usually confined to specific areas of the body, it may be widespread in severe cases: In young children, it typically occurs on the face, scalp, extremities, or trunk, and rarely occurs in the diaper area (show picture 3). In older children and adolescents, it is often accompanied by thickening and darkening of the skin, as well as scarring from repeated scratching. In adults, it commonly affects the back of the neck, the elbow creases, and the backs of the knees . Other affected areas may include the face, wrists, and forearms.
Diagnosis — There is no specific test used to diagnose eczema; diagnosis is usually based upon a person's history and the signs noted during a physical examination.
Factors that strongly suggest eczema include long-standing and recurrent itching, a personal or family history of allergic conditions, and an early age at onset. Other factors include a worsening of symptoms after exposure to certain triggers, and any of the skin findings noted above.
Allergy testing is usually reserved for people who have eczema in addition to features of asthma or allergic rhinitis. Allergy testing may also be recommended for children with suspected food allergies.
Treatment — Eczema is a chronic condition; it typically improves and then flares (worsens) periodically. Some people can have no symptoms for several years, only to have the disease return at a later time. It is not curable, although symptoms can be controlled with a variety of self-care measures and drug therapy. Eliminate exacerbating factors — Eliminating factors that worsen eczema can effectively control the symptoms. These factors may include frequent bathing and low-humidity environments (which can further dry the skin), emotional stress, rapid temperature changes, and exposure to certain chemicals and cleaning solutions. Common irritants include soaps and detergents, perfumes and cosmetics, wool or synthetic fibers, dust, sand, and cigarette smoke.
The following tips are recommended: Dust frequently and avoid placing upholstered furniture in the bedroom. Reducing exposure to house dust mites may reduce the severity of atopic dermatitis. Food allergies are relatively uncommon in adults, but may be a problem for a small percentage of infants and young children. However, changes to an infant or child's diet should be made only after consulting an allergy specialist because of the risk of eliminating a nutritionally important food group (eg, cow's milk, eggs, soy products). Emollients — Emollients are creams and ointments that moisturize the skin and can help relieve symptoms. The best emollients for people with atopic dermatitis are creams (such as Eucerin®, Cetaphil®, and Nutraderm®) and ointments (such as petroleum jelly, Aquaphor®, and Vaseline®). Emollients are most effective when applied immediately after bathing. Lotions should be avoided because they can worsen dry skin. Bathing — Lukewarm baths can hydrate and cool the skin, temporarily relieving the itching of eczema. Hot or long baths (greater than 10 to 15 minutes) and showers should be avoided since they can cause excessive drying. A mild soap or nonsoap cleanser (such as Cetaphil®) should be used sparingly. Application of an emollient immediately after bathing or showering prevents the drying that occurs through evaporation. Some experts recommend showers for their antibacterial effect, though individuals should determine which method is best for their situation. Topical steroids — Topical steroid creams and ointments are often effective for controlling mild to moderate atopic dermatitis. They are usually applied twice daily and help to reduce symptoms and moisturize the skin; non-medicated emollients can be resumed when symptoms resolve. Strong topical steroids may be needed to control severe flares of eczema; however, highly potent steroids should be used for only short periods of time to prevent thinning of the skin. Other topical treatments — Newer topical therapies for eczema include tacrolimus (Protopic®) and pemicrolimus (Elidel®). They are effective for controlling eczema in persons who have not improved with topical steroids, although do not work as quickly as topical steroids. They are useful in sensitive areas such as the face and groin, and can be used in children over age two. Due to safety concerns, it is recommended that these treatments be used only as instructed by a healthcare provider. Oral steroids — Oral steroids occasionally are used to treat a flare of chronic eczema, though should not be used on a regular basis because of side effects. Oral antihistamines — Oral antihistamines help relieve the itching of eczema and the accompanying eye irritation. The over-the-counter antihistamine diphenhydramine (Benadryl®), and other antihistamines, such as hydroxyzine and cyproheptadine, are most effective for eczema, although these drugs can cause drowsiness. The nonsedating antihistamines such as cetirizine (Zyrtec®) and loratadine (Claritin®) also may relieve symptoms, and loratadine is available without a prescription in the United States. Doxepin is an antidepressant that has antihistamine actions and may be recommended if other antihistamines are not helpful. Ultraviolet light therapy (phototherapy) — Ultraviolet light therapy (phototherapy) can effectively control atopic dermatitis. However, this therapy is expensive, may increase a person's risk for skin cancer, and is therefore recommended only for persons with severe eczema who do not respond to other treatments. Immunosuppressive drugs — Immunosuppressive drugs can effectively control severe eczema. These drugs include oral cyclosporine, tacrolimus, methotrexate, mycophenylate mofetil, and azathioprine. Treatment with these drugs can cause serious side effects, including an increased risk for infection, and their use is generally limited to persons who do not improve with other treatments.
SEBORRHEIC DERMATITIS — Seborrheic dermatitis causes overproduction of skin cells and sebum, the skin's natural oil. Seborrheic dermatitis usually occurs in areas of the body that have many oil-producing glands, including the scalp, face, upper chest, and back. It is most common during infancy; this is called cradle cap. Cradle cap usually resolves by 8 to 12 months of age.
Cause — The cause of seborrheic dermatitis is unknown, although it is known that an overgrowth of a normal skin yeast fungus occurs with this condition. It is not clear whether the fungus causes the flaking and redness or the increased flaking allows overgrowth of the fungus.
Symptoms — The symptoms of seborrheic dermatitis include redness, scaling, and itching of the affected skin. The dermatitis most often occurs on the scalp and face, especially on the eyebrows, the bridge and sides of the nose, and in the crease between the nose and lip (show picture 5). In men, seborrheic dermatitis is usually worse on the skin beneath mustaches and beards. Seborrheic dermatitis can also affect the chest, upper back, armpits, and pubic area, and the condition can affect the entire body in infants.
The term seborrhea refers to oiliness of the skin, without redness or scaling. Dandruff causes scalp scaling without redness, although it can commonly progress to seborrheic dermatitis of the scalp.
Diagnosis — There is no specific test for diagnosing seborrheic dermatitis. The diagnosis is usually based upon a person's history and the signs noted on physical examination. In rare cases, a skin biopsy (a collection of a small sample of skin tissue) may be necessary to confirm the diagnosis or rule out other conditions that mimic seborrheic dermatitis.
Treatment — The symptoms of seborrheic dermatitis can be effectively controlled with a combination of self-care measures and drug therapy. Washing and shampooing — Diligent washing and shampooing can control the symptoms of seborrheic dermatitis. Frequent washing counters the build-up of skin scales, and daily shampooing with a medicated shampoo controls scaling and itching on the scalp. For best results, the shampoo should be left in place for a few minutes before rinsing.
The growth of skin cells is slowed by shampoos that contain tar (Z-Tar®, Pentrax®, DHS tar®, Ionil T plus®, and T-Gel extra strength®), selenium sulfide (Selsun® and Exelderm®), and zinc pyrithione (Head and Shoulders®, Zincon®, and DHS zinc®). Shampoos containing antifungal medications (Nizoral®, Stieprox®) are quite effective. All of these shampoos can be used indefinitely. Topical steroids — Low potency topical steroids are usually the drugs selected first for the treatment of seborrheic dermatitis. These drugs are available in creams and lotions for the face and in alcohol-based liquids and aerosol sprays for the scalp. The topical steroids should be applied daily until the dermatitis improves; they can then be gradually discontinued. The lower potency steroid preparations are used, so that even prolonged use results in few, if any side effects. Topical antifungal drugs — The topical antifungal cream ketoconazole (Nizoral®) appears to be as effective as topical steroids for the treatment of seborrheic dermatitis. In cases of severe seborrheic dermatitis, treatment may include both topical steroids and topical antifungal drugs.
CONTACT DERMATITIS — Contact dermatitis refers to dermatitis that is caused by direct contact of the skin with a substance. The substance can be an allergen (a substance that provokes an immune reaction) or an irritant (a substance that directly damages the skin). The dermatitis results from contact with an irritant in about 80 percent of people with contact dermatitis.
Irritant contact dermatitis — Irritant contact dermatitis occurs when the skin comes in direct contact with a substance that physically, mechanically, or chemically irritates the skin.
Cause — The skin becomes inflamed when the normal skin barrier is irritated. The most common cause are products used on a daily basis, including soap, cleansers, and rubbing alcohol. Persons with other skin conditions, dry skin, and light-colored or "fair" skin are at greatest risk, although anyone can develop irritant dermatitis.
Symptoms — Mild irritants cause redness, dryness, and fissures (small cracks), with itching. Strong irritants cause swelling, oozing, tenderness, and blisters (show picture 6).
Irritant contact dermatitis most commonly affects the hands, often beginning in the area between the fingers. It can also affect the face, especially the eyelids.
Diagnosis — The diagnosis of irritant contact dermatitis is usually based upon a person's history and the physical examination. In some cases, a patch test (applying a small amount of the possible irritant to the skin) may be recommended to determine if the dermatitis is caused by an allergy.
Treatment — The treatment of irritant contact dermatitis helps to restore the normal skin barrier and protecting the skin from additional injury by the irritant. Reducing exposure to known irritants is essential. In some cases, simply reducing the use of soap and using emollient creams or ointment alleviates symptoms. Wearing gloves when working with irritants may help as well.
In more severe cases, topical steroids may be used. These are most effective when applied and covered with a barrier, such as plastic wrap, a gauze dressing, cotton gloves, or petroleum jelly. Oral steroids are not used for the long-term treatment of irritant contact dermatitis; however, they may be used briefly to treat severe dermatitis.
Allergic contact dermatitis — Allergic contact dermatitis occurs in some individuals when the skin comes in direct contact with an allergen. This activates the body's immune system, which triggers inflammation. Anyone can experience allergic contact dermatitis. Allergic contact dermatitis can occur when someone is newly exposed to a product, but can also occur after years of use.
Common allergens — Poison ivy, poison oak, and poison sumac are the most common contact allergens. (See "Patient information: Poison ivy"). Other common allergens include nickel (show picture 7) in jewelry, perfumes and cosmetics, components of rubber, nail polish, and chemicals in shoes (both leather and synthetic, show picture 8). Allergic contact dermatitis can also be triggered by certain medications, including topical hydrocortisone, topical antibiotics, benzocaine, and thimerosol.
Symptoms — Symptoms include intense itching and a red rash that develops quickly. The rash is usually limited to areas that were in direct contact with the allergen, but a rash can appear in other areas of the body if the allergen was transferred to those areas on a person's hands (show picture 9). Washing the allergen away with soap and water can usually prevent this spread.
The rash typically appears within 12 to 48 hours of exposure to the allergen, although in some cases it may not appear for up to two weeks. Less commonly, the rash persists for months or years, which makes it difficult to identify what caused the reaction.
Diagnosis — The diagnosis of allergic contact dermatitis is based upon a person's history and the signs noted during a physical examination. An improvement of symptoms after eliminating exposure to the suspected allergen supports the diagnosis. Patch testing (applying a small amount of the possible irritant to the skin) can be helpful in identifying the allergen.
Treatment — Allergic contact dermatitis usually resolves within two to four weeks after a person's exposure to the allergen stops. Several measures can minimize symptoms during this time and can help control symptoms in people who have chronic allergic contact dermatitis.
Whenever possible, identify and stop all exposure to the allergen. Topical steroids can alleviate inflammation. Calamine lotion may relieve mild symptoms.
For more severe symptoms, oral drugs, including steroids (such as prednisone) and antihistamines, may be recommended. Wet-to-dry compresses help dry out oozing skin and cool the skin, relieving severe itching. Wet-to-dry compresses can be easily made and applied at home as follows: Dampen a thin piece of fabric (such as one layer of a cotton or linen sheet) in water or a mixture of water and aluminum acetate (Burow's solution) Apply the dampened fabric to the affected skin Allow the fabric to dry over 15 to 30 minutes Remove the dry fabric gently Repeat the procedure several times
LATEX DERMATITIS — Latex is a fluid produced by rubber trees that is processed into a variety of products, including gloves, balloons, and condoms. In some individuals, exposure to these products and others (such as rubber bands, erasers, feeding nipples, pacifiers) can cause a contact dermatitis that is either an irritant or allergic reaction. Less commonly, a person can develop a potentially life threatening allergic reaction to latex.
Irritant dermatitis — Irritant dermatitis can occur while wearing latex gloves. It usually occurs on the hands of people who wear latex or other rubber gloves; the latex acts as an irritant and the gloves trap moisture against the skin. The skin dries out when the gloves are removed, leading to the dermatitis.
The symptoms of irritant rubber or latex dermatitis include redness and itching on the skin. There may also be dryness and cracking. Symptoms usually occur within 12 to 36 hours of contact with a latex product. Treatment involves avoiding use of any latex-containing products.
Latex allergy — Latex can trigger allergic contact dermatitis. The skin reaction caused by a latex allergy does not differ significantly from that of irritant latex dermatitis.
Some people with latex allergy have severe allergic reactions to latex, including swelling, sneezing, and wheezing. Rarely, anaphylaxis can occur, which causes life-threatening difficulty with breathing. Typically, the most severe allergic reactions occur during procedures when latex comes into contact with mucous membranes (such as in the mouth, vagina, or during surgical procedures). However, some people are so sensitive that severe reactions can occur with even brief contact. (See "Patient information: Anaphylaxis").
Latex allergy is most common among people who have undergone many surgeries and who have other allergic conditions. Latex allergy is also common among health care workers and workers in the latex industry, particularly those who have atopic dermatitis or a history of other types of allergies (such as allergic rhinitis or asthma).
Latex can become aerosolized (often from powder in gloves) and cause nasal symptoms and asthma in sensitized individuals. Some people with latex allergy may also develop reactions to certain foods, including avocado, kiwi, banana, and chestnuts.
Diagnosis — In most cases, the diagnosis of latex allergy is based upon a person's history of exposure. The more serious type of latex allergy causes an immediate onset of hives, nasal symptoms, swelling, or wheezing after latex exposure. Some of these individuals may need to see a dermatologist or allergist for specialized skin patch tests and blood testing to verify the latex allergy.
Treatment — The primary mode of treatment for latex allergy is to avoid all latex-containing products. Non-latex examination gloves are widely available, and use of glove liners may also be an effective approach. Natural membrane (sometimes called sheep skin) condoms may be used in place of latex condoms. Natural membrane condoms are effective for preventing pregnancy, but do not protect against transmission of sexually transmitted diseases such as HIV, gonorrhea, and chlamydia.
Those with serious latex allergy should wear a bracelet, necklace, or similar alert tag at all times. If a reaction occurs and the person is too ill to explain their condition, this will help responders get the proper care for the person as quickly as possible. This measure is especially important in children.
The alert tag should include a list of known allergies, as well as the name and phone number of an emergency contact. One device, Medic Alert®, provides a toll-free number that emergency medical workers can call to find out a person's medical history, list of medications, family emergency contact numbers, and healthcare provider names and numbers.
Persons with a latex allergy should inform their doctors, dentists, and other health care providers about the allergy. These individuals also may be advised to carry an anaphylaxis kit (containing epinephrine that can be injected under the skin) as a precautionary measure. Because latex allergy is common among people with spina bifida, doctors often recommend that people with this condition undergo a screening for latex allergies before any medical procedures are performed. (See "Patient information: Use of an epinephrine autoinjector").
DYSHIDROTIC DERMATITIS — Dyshidrotic dermatitis (also called pompholyx or dyshidrosis) is an intensely itching chronic, recurring dermatitis of unknown cause that typically involves the palms, soles, and fingers. Most people experience acute episodes of intense itching on the palms and/or soles that progress to multiple small vesicles (fluid-filled bumps), which peel off over one to two weeks, leaving cracks in the skin that slowly resolve (show picture 10). Recurrent episodes alternating with symptom-free periods are common.
Medium strength to potent topical steroids can control outbreaks in mild cases. Occasionally, brief courses of oral steroids are necessary to control symptoms. Local treatments with ultraviolet light therapy are helpful in people who have not responded to other measures.
NUMMULAR DERMATITIS — Nummular dermatitis causes intensely itchy patches of skin, with redness, small bumps, skin flaking, slight crusting, and some serous oozing on close inspection. A person may have as few as one lesion or as many as 20 to 50 lesions. Each lesion tends to be circular, measuring 2 to 10 cm in diameter.
Lesions are usually on the trunk and lower extremities, and the head is generally spared. The onset is usually spontaneous, and the cause often cannot be identified; some people may have exposures to drying or irritating substances (eg, excessive water exposure, chlorine, soaps).
A potent topical steroid ointment is the treatment of choice for nummular dermatitis. Systemic steroids in short courses are occasionally required. It may be helpful to avoid irritants, if they can be identified. Skin moisturization is an important part of the management of nummular dermatitis; a rich moisturizing cream should be applied immediately after bathing.
SUMMARY Dermatitis is defined as an inflammation of the skin; there are several different types of dermatitis. Atopic dermatitis (eczema) is a common chronic condition that causes skin to become red, itchy, and dry. People with other allergies are more likely to develop the condition; the diagnosis is often based on this as well as examination of the skin. Treatment includes avoiding things that make symptoms worse (such as dry air and irritating fabrics) and applying creams or ointments to soothe the itchy rash. (See "Atopic dermatitis (eczema)" above). Seborrheic dermatitis causes overproduction of skin cells and oil; it is most common in infants (cradle cap). This type of dermatitis causes redness, itching, and scaling of the skin, and often affects the face and scalp; it is diagnosed based on a person's history and examination of the skin. Symptoms can be controlled by washing the skin and hair carefully and applying creams to relieve itching and redness. (See "Seborrheic dermatitis" above). Irritant contact dermatitis is a reaction caused by contact with a substance that is irritating to the skin, such as a soap or cleanser. This can make the skin red, itchy, and dry. Persons with other skin conditions, dry skin, and light-colored or "fair" skin are at greatest risk, although anyone can develop irritant dermatitis. Diagnosed may be done by testing the skin's reaction to a very small amount of the irritant; avoiding the substance usually relieves symptoms, but medicated creams may be prescribed in severe cases. (See "Irritant contact dermatitis" above). Allergic contact dermatitis occurs when the skin touches a substance that not only irritates, but actually causes an allergic reaction (such as with poison ivy). A rash appears where contact occurred, and usually resolves on its own if the substance is avoided; creams or compresses may be used to relieve itching and inflammation. (See "Allergic contact dermatitis" above). Latex dermatitis is caused by contact with latex (eg, latex gloves). Some people have a serious, life-threatening allergy to latex, and must be very careful to avoid it. (See "Latex dermatitis" above). Dyshidrotic dermatitis is a condition that causes intense itching and bumps, often on the palms of the hands and soles of the feet; steroids that are applied to the skin or taken as a pill are often used to treat this condition. (See "Dyshidrotic dermatitis" above).
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html) National Institute on Arthritis and Musculoskeletal and Skin Diseases
(www.niams.nih.gov/hi/index.htm) American Academy of Dermatology
(www.aad.org) American Academy of Allergy, Asthma and Immunology
(www.aaaai.org) EczemaNet
(www.skincarephysicians.com/eczemanet/) National Eczema Association for Science and Education
(www.eczema-assn.org)
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