An otherwise healthy 28-year-old man with a history of allergic rhinitis was seen for a rash of the legs. The lesions had developed intermittently during the past 3 months. Physical examination revealed six 1- to 2-cm annular, erythematous, nonscaly plaques of the thighs with a cayenne pepper–like appearance, suggesting a pigmented purpuric dermatosis (PPD) (Figure 1). A biopsy specimen of a lesion revealed histologic findings consistent with PPD (Figure 2). Microscopically, there was a superficial, perivascular, lymphocytic infiltrate with extravasation of erythrocytes in the papillary dermis. The patient was a weightlifter and had been taking a commercial dietary supplement containing creatine and hydroxymethylbutyrate for the past 6 years. It was decided that the patient should discontinue taking this supplement, and within 2 weeks, the lesions had resolved leaving some mild postinflammatory changes. A rechallenge with the supplement was not undertaken.
Chorny JA, Cohen J. Pigmented Purpuric Dermatosis Associated With Creatine Supplementation. Arch Dermatol. 2006;142(12):1650-1666. doi:10.1001/archderm.142.12.1662