Fig. 167.3 (A) Group A streptococcal infection involving perianal area. Moist erythema of the folds is characteristic. (B) Allergic contact diaper dermatitis from disposable diaper components; called “Lucky Luke dermatitis” by the authors after a cartoon character who carries his holster in the same area. (C) Seborrheic dermatitis, a cause of diaper rash in young infants. This type of dermatitis is difficult to distinguish clinically from infantile psoriasis but tends to be less erythematous, to have thinner scaling, and to respond more quickly to topical anti-inflammatory medications. (D) Typical diaper involvement of psoriasis. (E) Staphylococcal infection with both pustules and bullae in an 11-day-old infant.