[Acne inversa in Crohn's disease].

We report 2 patients with the association of Crohn's disease and acne inversa (= hidradenitis suppurativa). A 50-year-old woman with a 10-year-history of Crohn's disease developed suppurative nodules and abscesses in the genitoanal region. Over several years these lesions were hidden from everybody including the family physician. In a 42-year-old female patient abscesses appeared in the axilla 4 years after the diagnosis of Crohn's disease. During the next years these draining lesions also developed in both groins and the perineum. The differential diagnosis included cutaneous manifestations of Crohn's disease in both cases. The clinical picture with draining abscesses and sinuses with communicating channels, cystic nodules, hypertrophic scars and foul-smelling discharge were typical findings of acne inversa. In the last years this entity was reported several times in patients with Crohn's disease. Acne inversa starts with a compact hyperkeratosis of the infundibulum in terminal hair follicles, followed by a segmental rupture of the follicular epithelium and a spreading inflammatory reaction. As pathogenic factors genetic disposition and smoking were discussed. The only curative therapy is excision of the affected area. The reported association should be known in order to recognize the disease and institute the right therapy.