Overall and Subgroup Prevalence of Pyoderma Gangrenosum Among Patients with Hidradenitis Suppurativa: a population based analysis in the United States.

BACKGROUND: Hidradenitis suppurativa (HS) and pyoderma gangrenosum (PG) are reported to coexist, although prevalence of PG among HS patients has not been systematically evaluated.

OBJECTIVE: To evaluate PG prevalence among HS patients.

METHODS: Cross-sectional analysis of adults with PG among HS and non-HS patients using electronic health records data from a population-based sample of 55 million patients.

RESULTS: Prevalence of PG among 68,232 HS patients was 0.18% (125/68,232), compared to 0.01% (1,835/31,435,166) among those without HS (p<0.0001). Prevalence was markedly higher among HS patients having Crohn's disease (CD) (3.68%), compared to HS patients without CD (0.12%). Odds of having PG was 21.14 (95% CI 17.51-25.51) times greater among HS patients compared to patients without HS. HS patients with CD had 12.38 (95% CI 9.15-16.74) times the odds of having PG compared to non-HS patients with CD. Among patients without CD, those with HS had 26.51 (95% CI 21.07-33.36) times the odds of having PG compared to non-HS patients.

LIMITATIONS: We could not establish HS phenotype among those having coexistent PG, nor could we distinguish syndromic from non-syndromic cases.

CONCLUSION: HS patients have increased prevalence of PG, regardless of CD status. Painful ulcerations among HS patients warrant additional evaluation for PG.