Hydradenitis suppurativa and inflammatory bowel disease: An unusual, but existing association.

Inflammatory bowel disease (IBD) could be associated with several extra-intestinal manifestations (EIMs) involving musculoskeletal, hepatopancreatobiliary, ocular, renal, and pulmonary systems, as well as the skin. In the last years, hidradenitis suppurativa (HS) is acquiring an increasing interest. IBD, especially Crohn's disease (CD), is among the most reported associated diseases in HS patients. The aim of this paper is to give a brief overview of data showing a possible epidemiologic and pathogenetic association between IBD and HS. We performed a pooled-data analysis of four studies and pooled prevalence of HS in IBD patients was 12.8%, with a 95%CI of 11.7%-13.9%. HS was present in 17.3% of subjects with CD (95%CI: 15.5%-19.1%) and in 8.5% of UC patients (95%CI: 7.0%-9.9%). Some items, especially altered immune imbalance, are generally involved in IBD pathogenesis as well as invoked by HS. Smoking is one of the most relevant risk factors for both disorders, representing a predictor of their severity, despite, actually, there being a lack of studies analyzing a possible shared pathway. A role for inheritance in HS and CD pathogenesis has been supposed. Despite a genetic susceptibility having been demonstrated for both diseases, further studies are needed to investigate a genetic mutual route. Although the pathogenesis of IBD and HS is generally linked to alterations of the immune response, recent findings suggest a role for intestinal and skin microbiota, respectively. In detail, the frequent finding of Staphylococcus aureus and coagulase-negative staphylococci on HS cutaneous lesions suggests a bacterial involvement in disease pathogenesis. Moreover, microflora varies in the different cutaneous regions of the body and, consequently, two different profiles of HS patients have been identified on these bases. On the other hand, it is well-known that intestinal microbiota may be considered as "the explosive mixture" at the origin of IBD despite the exact relationship having not been completely clarified yet. A better comprehension of the role that some bacterial species play in the IBD pathogenesis may be essential to develop appropriate management strategies in the near future. A final point is represented by some similarities in the therapeutic management of HS and IBD, since they may be controlled by immunomodulatory drugs. In conclusion, an unregulated inflammation may cause the lesions typical of both HS and IBD, particularly when they coexist. However, this is still a largely unexplored field.

Neutrophilic eccrine hidradenitis: a case report of an unusual annular presentation.

Neutrophilic eccrine hidradenitis (NEH) is an acute, self-limited, inflammatory neutrophilic dermatosis. It is most commonly described in patients with acute myelogenous leukemia (AML) following chemotherapy. NEH generally presents as erythematous papules and plaques on the head, trunk, and extremities. Histologically, NEH is characterized by a neutrophilic infiltrate surrounding eccrine ducts and coils with occasional necrosis. We describe a case of NEH with an unusual presentation of annular plaques. A search of the literature revealed only one other case report of NEH presenting as an annular eruption.

The possible role of Chlamydia trachomatis in perineal suppurative hidradenitis.

OBJECTIVE: To find out if there is an association between perineal suppurative hidradenitis and Chlamydia trachomatis infection. DESIGN: Open study. SUBJECTS: Seven consecutive patients treated for perineal suppurative hidradenitis during the past three years, and 10 control subjects who were being treated for acute cryptogenic perianal abscesses. MAIN OUTCOME MEASURE: Presence of C. trachomatis detected by direct immunofluorescent staining. RESULTS: All but one patient had serological evidence of C. trachomatis infection. All 10 control subjects failed to react to IgA antibodies to C. trachomatis, and two reacted to IgG antibodies. CONCLUSION: There may be a link between C. trachomatis infection and suppurative hidradenitis, but it is uncertain whether it is a direct cause or a predisposing factor.