Pyoderma Gangrenosum of the Scalp: A Rare Clinical Variant.

Pyoderma gangrenosum (PG) is a rare, neutrophil-predominant dermatosis that usually presents as a papule or pustule and progresses into a painful ulcer. Clinical and histopathological features are nonspecific, making PG a challenging condition to diagnose. Lesions may occur anywhere on the body; however, the lower extremity is the most common location. Solitary lesions in atypical locations such as the scalp are uncommon, making this clinical variant especially difficult to recognize and diagnose. Although the clinical features and subsequent management of scalp PG might be different from other anatomic sites, the typical presentation and treatment of scalp PG is still unclear. The authors present a recent case of a 34-year-old woman with scalp PG and summarize 16 other cases documented in the literature. This case report and literature review illustrate several similarities and differences between scalp PG and classic PG: (1) scalp PG occurs in a wider age demographic of patients; (2) as with classic PG, inflammatory bowel disease and pregnancy are associated conditions, but head injury and preexisting inflammatory skin conditions of the scalp may be additional predisposing factors for scalp PG; and (3) as with classic PG, scalp PG generally responds well to corticosteroids and immunosuppressive therapy. Scarring occurs in all conditions, though disfigurement and psychosomatic effects may be disproportionately higher in scalp PG.