Hidradenitis suppurativa and pyoderma gangrenosum: A common autoinflammatory broad spectrum

Hidradenitis suppurativa (HS) and pyoderma gangrenosum (PG) are chronic inflammatory skin conditions with distinct clinical presentations, but with an increasing recognition of their overlapping pathogenic mechanisms. HS primarily affects areas rich in apocrine glands and is characterized by painful nodules, abscesses, and draining sinus tracts, which often progress to scarring. PG, in contrast, presents as rapidly progressive, painful ulcers with neutrophilic infiltration, commonly affecting the lower limbs and trunk. Both conditions are associated with autoinflammatory syndromes, such as PASH and PAPASH, and are characterized by immune dysregulation involving cytokines such as TNF-α, IL-1β, IL-17 and IL-23.

We present two rare cases of concomitant HS and PG. The first case is a 51-year-old male with a 20-year history of severe HS who developed PG lesions on his lower limbs, later managed with dapsone and adalimumab. The second case describes a 58-year-old male with a 12-year history of HS who recently developed PG lesions associated with underlying inflammatory bowel disease (IBD). Both patients exhibited elevated inflammatory markers and histopathological confirmation of PG.

These cases highlight the importance of recognizing the co-occurrence of HS and PG, as this may represent a late or systemic manifestation of a common autoinflammatory disorder. Early identification and targeted treatment with biologics, particularly TNF-α inhibitors, may offer improved disease control and patient outcomes. Due to the rarity of these conditions and the associated diagnostic challenges, further case reports and studies are crucial for improving our understanding of their shared pathophysiological mechanisms and refining therapeutic strategies.