Atopic Dermatitis (Eczema)
Summary
Atopic dermatitis (also referred to as eczema) is a chronic, itchy, inflammatory skin disease that occurs most frequently in children, but also affects adults. It is often associated with a personal or family history of asthma and allergies. These three conditions together are known as the “atopic triad”. While the exact cause is unknown, the best treatment is topical corticosteroids.
Figure 1. Atopic Triad
Atopic dermatitis affects 5-20% of children worldwide; in the US the incidence is approximately 11%. Adults are affected in similar amounts. Most cases of atopic dermatitis will begin by the age of 5. Patients with a family or personal history of components of the atopic triad (atopic dermatitis, asthma, allergies) are at an increased risk for developing these conditions. This suggests a genetic component of the condition. Some studies have found mutations in proteins involved in skin barrier function such as filaggrin. The incidence of atopic dermatitis is also increasing in developed countries suggesting an environmental component may be involved.
Atopic dermatitis is diagnosed by a dermatologist based on clinical findings including history, morphology and distribution of skin lesions, and other associated signs. A dermatologist will look for evidence of dry itchy skin, involvement of skin folds (elbows, knees, neck, ankles), and a history of allergies/asthma.
Other conditions can be confused with atopic dermatitis. Allergic or irritant contact dermatitis should be considered when the rash occurs in a suspect location such as under a watch strap, a neckline, or the hands and face. Allergic reactions can be caused by metal, plants, soaps, fragrances, among others chemicals where irritant reactions occur due to friction, pressure, and sweating in an otherwise non-allergenic material. Seborrheic dermatitis is common in infants and presents with greasy scale and involvement of the scalp. Psoriasis can cause a red itchy rash, but occurs in different locations than atopic dermatitis and rash is more plaque like. If multiple members of a household suddenly start itching, scabies should be considered.
Infant with eczema, DermNet.nz
Child with eczema on the back of the knees, DermNet.nz
Hyperpigmentation of lesions, DermNet.nz
Eczema of the hand
Infant with eczema, DermNet.nz
Child with eczema on the back of the knees, DermNet.nz
Hyperpigmentation of lesions, DermNet.nz
Eczema of the hand
The optimal management of atopic dermatitis requires a multipronged approach that involves the elimination of exacerbating factors, restoration of the skin barrier function and hydration of the skin, and pharmacologic treatment of skin inflammation.
Elimination of exacerbating factors: Factors that disrupt an already abnormal skin barrier include excessive bathing without subsequent moisturization, dry environments, emotional stress, untreated dry skin, overheating of skin, and exposure to solvents and detergents. While some allergens (pollen, certain foods, dust mites) may be associated with atopic dermatitis, removal does not necessarily improve the condition as would be expected.
Maintaining skin hydration: Lotions, which have a high water and low oil content, can worsen dry skin and trigger a flare of the disease. In contrast, thick creams (eg, Eucerin, Cetaphil, Cerave), which have a low water content, or ointments (eg, petroleum jelly, Vaseline, Aquaphor), which have zero water content, better protect against dry skin. Patients often complain that ointments are greasy, but they are the best way to prevent dry skin. Using ointments at night can minimize this burden. Use your moisturizer at least two times per day, typically after bathing and hand washing.
Controlling itch: Antihistamines such as OTC Zyrtec or OTC Claritin may be helpful in reducing itch. Your dermatologist can prescribe a stronger antihistamine or other topical medications such as doxepin if these are ineffective. The most common side effect with antihistamines is drowsiness which can be minimized by taking medication at night. Newer antihistamines are less likely to cause drowsiness. It is critical to avoid itching. While tough to control, itching starts the “itch - scratch cycle” where itching causes break down the skin barrier allowing more allergens and outside material to enter the skin. This in turn causes more inflammation, further breaking down the skin barrier making the itching even worse!
Figure 2. Itch-Scratch Cycle
Topical corticosteroids: For patients with mild disease and in sensitive locations (such as the face/skin folds), low potency corticosteroids such as hydrocortisone 2.5% or desonide 0.05% are recommended. While medications come in creams and ointments, ointments are typically more effective for those that can tolerate the greasy nature of the medication. Side effects for mild topical corticosteroids are minimal, but a full list is available with your medication. For patients with moderate disease, medium potency corticosteroids such as triamcinolone 0.1% and betamethasone 0.05% are recommended. These both come in many forms including creams, ointments (and even foams), but ointments are typically the most effective. Side effects may include thinning of the skin if used for prolonged periods on the face and skin folds. On thicker parts of the skin and areas with active inflammation, this risk is minimal. For severe, acute flares, high strength corticosteroids are available for limited use. Please consult your dermatologist for more information.FAQs
The most common reason patients fail to see improvement is not regularly using topical medications for a sufficient duration. Topical corticosteroids should be applied two times per day (or as directed by your physician) for between 2 and 4 weeks to see improvement. New skin cells take a month to reach the surface. Medication you apply today can affect new skin a month from now.
Lotions are made from a water base and can make dryness worse. Creams are made from an oil base mixed with water. Ointments are made entirely from oil and are considered the best protection for the skin. The same strength prescription topical corticosteroid can be considerably more effective as an ointment than as a cream. A reason to choose a cream would be for insurance reasons (if it is considerably cheaper) or if the patient will not use an ointment.
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