This condition is the most common of all pediatric dermatoses. For the majority of patients, the onset occurs during infancy. The classic clinical appearance in this age group is illustrated in Figs. 8-1, 8-2, 8-3. There are symmetrical patches of erythema, exudation, and scale involving the cheeks and chin. It is not unusual also to see widespread involvement of the trunk and extensor extremities during infancy; the diaper area is most often spared.
Figure 8-4 shows similar distribution in an older child. In this case, impetiginization may be contributing to the crusted appearance of the lesions. Pruritus is a cardinal feature of atopic dermatitis and may be evidenced in the infant by irritability, scratching, and rubbing against nearby objects. Atopic dermatitis is an inherited disorder. Children with the disease most often have a family history of the atopic diathesis (atopic dermatitis, asthma, or allergic rhinitis) and may themselves manifest asthma or allergic respiratory disease.
When the diagnosis of atopic dermatitis is in doubt, the search for associated clinical findings is often helpful. Two such near-pathognomonic cutaneous signs of atopic dermatitis are pictured here. The Dennie-Morgan line (Fig. 8-5) is a double fold under the eye, which is seen in many children with atopic dermatitis. Figure 8-6 shows another telltale sign: a fissure at the junction of the pinna of the ear and the face. Other associated findings related to atopic dermatitis include pityriasis alba (Figs. 8-16 and 8-17), keratosis pilaris (Figs. 8-46 and 8-47), lichen spinulosus (Figs. 9-56 and 9-57), and ichthyosis vulgaris (Figs. 12-1, 12-2, 12-3). Children with atopic dermatitis are also frequently noted to have hyperlinear palms and soles. Keratoconjunctivitis and cataracts may occur in the child with atopic dermatitis.
During childhood, the most common locations of atopic dermatitis are the antecubital and popliteal fossae and the posterior neck. Pictured here are children in whom the involvement is more widespread. The lesions show the characteristic erythema, oozing, and crusting of acute atopic dermatitis. This appearance correlates with the histopathology. Spongiosis and intracellular edema are cardinal features of acute lesions; chronic plaques show acanthosis and hyperkeratosis. The pathogenesis of atopic dermatitis remains a mystery. Patients with the disease seem to have altered autonomic function and increased plasma histamine levels. Many have elevated levels of IgE, but some are completely normal in this ...