A 5-month-old Hispanic infant presented to our clinic with a 4-month history of a rash on his scalp, diaper area, and folds of his body. Prior to seeing us, he had undergone treatment with various topical (nystatin, zinc oxide, pimecrolimus, mometasone, and clotrimazole) and oral medications (prednisolone, cephalexin, and cefdinir) that did not improve the rash.
The infant was born at 37 weeks' gestation and was otherwise healthy. A nodule on his scalp was noticed by his mother at approximately age 3 months. On examination, the patient had diffuse, greasy, scaly patches covering most of his scalp (Figure 1A) and erythematous, macerated patches around his neck, popliteal fossa, axillae, and groin. On his trunk, there were scattered pink papules and hypopigmented macules. The differential diagnosis included diffuse Langerhans cell histiocytosis (LCH), cutaneous candidiasis, atopic dermatitis, and Wiskott-Aldrich syndrome. He also had a 3-cm, soft, nonfluctuant, subcutaneous nodule on the right parietal scalp (Figure 1A). The differential diagnosis for the nodule included lipoma, hematoma, eosinophilic granuloma, epidermal inclusion cyst, abscess, encephalocele, meningocele, and neuroblastoma.
Fiala KH, Wells MJ, Stetson CL, Cecalupo AJ. When a Bump Can Be a Hole. Arch Dermatol. 2007;143(8):1073-1087. doi:10.1001/archderm.143.8.1083