Association and management of Crohnʼs disease plus hidradenitis suppurativa

Crohn's disease (CD) and hidradenitis suppurativa (HS) are both chronic inflammatory diseases in organs inhabited by commensal microorganisms, related to smoking and genetic etiologic compounds. Although the former affects primarily the gastrointestinal tract (GIT) and the latter concerns the skin, their probable association suggests a common treatment.1 Anti-tumor necrosis factor alpha (TNF-α) has been used in patients with CD and some reports show remission of HS with it2; therefore, it was tried in our patient, a 26-year-old woman, Brazilian, nonsmoker, with a 6-year diagnosis of fistulizing rectovaginal CD. At first an advancement flap technique was tried, unsuccessfully. Then infliximab treatment was initiated (standard dose), closing the fistula. One year later, she developed a perineal HS, confirmed by histopathologic exam, successively treated with ciprofloxacin, cephalexin, and sulfamethoxazole/trimethoprim, presenting partial response only to the latest association. A surgical resection of the lesions was performed but they relapsed on two other occasions, requiring new resections. Although the rectovaginal fistula remained closed, the history of relapsing HS led to increasing the infliximab dose to 10 mg/kg. After 6 months without improvement, adalimumab was chosen (standard dose), with persistence of the abscesses (Figs. 1, 2). Hidradenitis suppurativa lesion and scar from previous resection. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] Inflammatory process around hair follicle (H&E, 100×). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] CD is an inflammatory bowel disease of unknown cause. It is more frequent in American or European white women, smokers, between 20–40 years old, in urban areas. Adding to the epidemiology, there are a few other factors: genetic (NOD2 gene mutation in 15%–20% of the patients, HLA-DR1/DQw5, HLA-A2, and HLA-DRB3*0301 carriers are more likely to develop the disease), intraluminal (greater amount of bacteria in the GIT), intestinal permeability (increased and with a minor tissue repair rate), and immunoregulation failure (antigen presentation directed to Th1 response rather than suppressor T response).3 HS consists of recurrent nodules, abscesses, or sinus tract in apocrine gland-bearing areas, such as the axilla, groin, and perineum. Its prevalence is estimated around 1%, and its pathogenesis is based on infundibular hyperkeratosis leading to pilosebaceous follicular occlusion, with posterior dilatation and rupture, occasionally forming granuloma. The disease etiology might be related to Toll-like receptor 2 (TLR2), since the receptor is hyperexpressed in the leukocyte infiltration of the lesion, endorsing the hypothesis of an inappropriate immune response, as in CD.4 The association between CD and HS was observed in a study with 61 HS patients; 24 (39%) had lesions suggestive of CD. In a major research study, 18 (0.6%) out of 2926 CD patients presented with HS. The study also showed that 78% of those who had both diseases were smokers. The patients affected by CD and HS differ from the others by more frequent colon and perianal involvement, greater need for immunosuppression, and definitive ileostomy and proctectomy.5 The treatment of HS in CD patients is particularly difficult. In spite of some successful cases treated with infliximab,6 we did not attain the same result. In CD, when this therapy fails adalimumab is the second choice of anti-TNF-α. Following this line, in addition to considering their possible association and the cases of isolated HS responsive to adalimumab,7 we tried the same substitution, with no success. Perhaps the treatment time is an important factor in HS involvement, since good results were obtained with an extended use (2 years) of Infliximab,8 while the patient in question has not yet responded to anti-TNF-α with respect to the HS. It is not clear why different patients react in such different ways undergoing the same treatment. Further and more detailed studies are necessary to elucidate those differences and how they affect the therapeutic management of CD and HS.