The differential diagnosis and comorbidity of hidradenitis suppurativa and perianal Crohn's disease.

Over the last 8 years, 61 patients with hidradenitis suppurativa (HS) have been treated at this institution. Twenty-four have also had a diagnosis of Crohn's disease (38%). This dual pathology is examined in detail in this retrospective review. There were 11 males and 13 females with a mean age of 39 years (range 18 to 75 years). The Crohn's disease was ileal in 1 patient, ileocolic in 4, and affected the large bowel only in 19. The diagnosis of Crohn's disease predated that of HS by an average of 3.5 years. At the time of review, 22 patients had a stoma, 23 had undergone laparotomy and 17 had lost their rectum. Hidradenitis suppurativa occurred in the perineal or perianal area in all patients but involved other sites in 20 cases. Skin grafting had been done in 9 and local procedures in 19 patients. Granulomas were found in excised skin in 6 cases but this finding was not associated with a poor outcome. At a mean follow-up of 3.2 years from the most recent surgery for HS (range 1 to 11 years) 11 were asymptomatic for HS, 11 had symptoms and no follow up was available in 2. These data show that HS may coexist with Crohn's proctocolitis, complicating the diagnosis and management of patients in whom it occurs. An increased appreciation of the possibility is recommended.