title: Unilateral rash on a baby girl.
abstract: An 11-month-old baby girl came to the clinic with a pruritic rash. The rash initially appeared in her popliteal fossa 2 weeks before the visit. The eruption extended to the right leg, arm, and flank the week before the visit, subsequently spreading to the contralateral flank. Three weeks before to the eruption's appearance, the patient had an upper respiratory infection with a dry nonproductive cough, which resolved spontaneously without antibiotics. The physical examination revealed a healthy-appearing infant girl with excoriated erythematous papules coalescing into plaques on her right flexural arm that continued to the axilla and down the right flank to the flexural aspect of her leg (Figure 1). Her left side was essentially free of any rash (Figure 2). No cervical or axillary lymphadenopathy was noted, and the remainder of her exam was normal. What is your diagnosis? How would you manage this condition?
authors.affiliation: Wellman Center for Photomedicine (BAR 314), Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, 40 Blossom Street, Boston, MA 02114, USA. amorkh@pol.net
authors.forename: Amor
authors.initials: A
authors.lastname: Khachemoune
authors.forename: Ben N
authors.initials: BN
authors.lastname: Lockshin
authors.forename: Hazem
authors.initials: H
authors.lastname: El-Gamal
mesh_terms: D003937:Diagnosis, Differential; D005076:Exanthema / Q000209:etiology / Q000473:pathology* / Q000628:therapy; D005260:Female; D006801:Humans; D007223:Infant; D012075:Remission, Spontaneous