Abstract
Pyoderma gangrenosum is a rare, immune-mediated skin disease that belongs to neutrophilic dermatoses. It typically affects the lower extremities, making isolated involvement of the axillary regions a significant diagnostic challenge.
We present a clinical case of a 34-year-old patient with a nine-month history of the disease, manifested by painful ulcerative-erosive eruptions in the axillary areas. At the pre-hospital stage, pyoderma, allergic contact dermatitis, dermatophytosis, and pemphigus vegetans were incorrectly diagnosed, which is confirmed by the lack of therapeutic effect from antibacterial and antimycotic therapy. The diagnosis of pyoderma gangrenosum was verified based on the characteristic clinical presentation (multiple deep ulcerative defects with undermined edges of a bright red-pink color with a bluish tinge, the bases of the ulcers are covered with a purulent-necrotic scab) and histological examination results. Systemic glucocorticosteroid therapy (prednisolone 85 mg/day) was effective and led to regression of the lesions; however, disease recurrence occurred when the dose was reduced to 35 mg/day.
This case underscores the critical importance of early differential diagnosis of pyoderma gangrenosum in intertriginous zones to prevent iatrogenic complications and the pathergy phenomenon.