A 6-month-old infant presents with intensely pruritic, erythematous, papulovesicular lesions with excoriations and crusting primarily on the cheeks, scalp, and extensor surfaces of the arms and legs. The mother reports a family history of asthma and allergic rhinitis. Which of the following is the most likely diagnosis?

Explanation

The clinical presentation of intensely pruritic, erythematous, papulovesicular lesions with excoriations and crusting on the cheeks, scalp, and extensor surfaces in an infant, coupled with a family history of atopy (asthma, allergic rhinitis), is highly characteristic of atopic dermatitis. Atopic dermatitis typically presents in infancy with facial and extensor involvement, and pruritus is a hallmark symptom. The 'atopic triad' (eczema, asthma, allergic rhinitis) strongly supports this diagnosis. B. Seborrheic dermatitis typically presents with greasy, yellowish scales on an erythematous base, often affecting the scalp (cradle cap), face (eyebrows, nasolabial folds), and intertriginous areas. While it can occur in infants, the intense pruritus and papulovesicular lesions are less typical. C. Contact dermatitis would require exposure to an irritant or allergen, and while possible, the widespread distribution and strong atopic history make atopic dermatitis more likely. D. Psoriasis in infants (diaper psoriasis or napkin psoriasis) can occur, but it typically presents with well-demarcated erythematous plaques with silvery scales, and intense pruritus is less prominent than in atopic dermatitis. The morphology described is not typical for psoriasis.