Concurrent Presentation of Nocardia abscessus Infection and Pyoderma Gangrenosum Following Trauma.

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis characterized by painful skin ulcers with undermined borders and surrounding erythema. Cutaneous nocardiosis can present similarly, as ulcerative lesions, often following mechanical trauma, which is a shared risk factor for both conditions. In this case report, we describe an elderly patient on low-dose corticosteroids for polymyalgia rheumatica who developed rapidly progressive skin ulcers after sustaining a mechanical injury while gardening. The patient did not respond to broad-spectrum antibiotics. Histopathological examination of a skin biopsy revealed features consistent with PG, while culture of the same biopsy grew Nocardia abscessus. The patient was treated with a combination of high-dose corticosteroids, trimethoprim-sulfamethoxazole, and doxycycline, leading to complete clinical recovery with residual post-inflammatory hyperpigmentation. This case underscores mechanical trauma as a shared risk factor for the development of both PG and cutaneous nocardiosis. We hypothesize that the patient developed PG through the pathergy phenomenon following the initial injury and concomitantly developed N. abscessus infection. Chronic low-dose corticosteroid therapy likely was an additional risk factor for the development of cutaneous nocardiosis. However, the intriguing question remains whether N. abscessus infection itself could act as a trigger for the development of PG.