Autoinflammatory Syndromes of Hidradenitis Suppurativa: Updates in Clinical Features, Emerging Associations, and Management.

PURPOSE OF REVIEW: To summarize and critically evaluate recent literature on autoinflammatory syndromes of hidradenitis suppurativa (HS). RECENT FINDINGS: HS-associated autoinflammatory syndromes traditionally encompass pyoderma gangrenosum (PG), acne, and HS (PASH); pyogenic arthritis, PG, acne, and HS (PAPASH); psoriatic arthritis, PG acne, and HS (PsAPASH); and PG, acne, HS and ankylosing spondylitis (PASS). However, this spectrum continues to expand, with recent literature considering the inclusion of additional autoinflammatory diseases such as HS associated with SAPHO, including synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO); and Hyperimmunoglobulin D Syndrome (HIDS). HS-associated autoinflammatory syndromes are thought to be driven by dysregulation of the innate immune system and the subsequent overexpression of key inflammatory cytokines such as IL-1, and targeted IL-1 therapies have demonstrated particularly brisk and efficacious response. Multiple genes related to follicular keratinization or inflammatory regulation have been implicated, and sequencing methods such as whole-exome sequencing and variant enrichment analysis continue to identify novel genetic variants and are being used to further elucidate genotype-phenotype correlations. HS-associated autoinflammatory syndromes are an evolving spectrum of rare, severe, diseases in which HS coexists with other autoinflammatory conditions, most commonly PASH and related syndromes. They are driven by innate immune dysregulation and pathogenic genetic variants, with whole-exome sequencing aiding diagnosis and genotype-phenotype correlation. Management is often challenging and highly individualized, with targeted biologic therapies such as IL-1 inhibitors showing the most consistent and rapid clinical benefit.