ESSENTIALS OF DIAGNOSIS
Pruritic, xerotic, exudative, or lichenified eruption on face, neck, upper trunk, wrists, and hands and in the antecubital and popliteal folds.
Personal or family history of atopy (eg, asthma, allergic rhinitis, atopic dermatitis).
Tendency to recur.
Onset in childhood most common; onset after age 30 is uncommon.
Atopic dermatitis (also known as eczema) has distinct presentations in people of different ages and races. Diagnostic criteria for atopic dermatitis must include pruritus, typical morphology and distribution (flexural lichenification, hand eczema, nipple eczema, and eyelid eczema in adults), onset in childhood, and chronicity. Also helpful are (1) a personal or family history of atopy (asthma, allergic rhinitis, atopic dermatitis), (2) xerosis-ichthyosis, (3) facial pallor with infraorbital darkening, (4) elevated serum IgE, and (5) repeated skin infections.
Itching is a key clinical feature and may be severe and prolonged. Ill-defined, scaly, red plaques affect the face, neck, and upper trunk. The flexural surfaces of elbows and knees are often involved (eFigure 6–63). In chronic cases, the skin is dry and lichenified (eFigure 6–64). In patients with darker skin with severe disease, pigmentation may be lost in lichenified areas. During acute flares, widespread redness with weeping, either diffusely or in discrete plaques, is common. Virtually all patients with atopic dermatitis have skin disease before age 5; therefore, a new diagnosis of atopic dermatitis in an adult over age 30 should be made only after consultation with a dermatologist.
Atopic dermatitis on flexural surface of elbows. (Used, with permission, from Lindy Fox, MD.)
Ichthyosis vulgaris. Plate-like scales on the dorsal foot. (Used, with permission, from Lindy Fox, MD.)
Food allergy is an uncommon cause of flares of atopic dermatitis in adults. Eosinophilia and increased serum IgE levels may be present.
Atopic dermatitis must be distinguished from irritant or allergic contact dermatitis. Seborrheic dermatitis is less pruritic, with frequent scalp and central face involvement, greasy and scaly lesions, and responds quickly to therapy. Psoriasis is marked by sharply demarcated thickly scaled plaques on elbows, knees, scalp, and intergluteal cleft. Secondary staphylococcal or herpetic infections may exacerbate atopic dermatitis and should be considered during hyperacute, weeping flares. An infra-auricular fissure is a cardinal sign of secondary staphylococcal infection.
Patient education regarding gentle skin care and proper use of medications is critical to successful management of atopic dermatitis.