title: Hydradenitis suppurativa and inflammatory bowel disease: An unusual, but existing association.
abstract: 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.
authors.affiliation: Mariabeatrice Principi, Antonella Contaldo, Andrea Iannone, Giuseppe Losurdo, Michele Barone, Enzo Ierardi, Alfredo Di Leo, Gastroenterology Section, Department of Emergency and Organ Transplantation, University of Bari, 70124 Bari, Italy.
authors.forename: Mariabeatrice
authors.initials: M
authors.lastname: Principi
authors.affiliation: Mariabeatrice Principi, Antonella Contaldo, Andrea Iannone, Giuseppe Losurdo, Michele Barone, Enzo Ierardi, Alfredo Di Leo, Gastroenterology Section, Department of Emergency and Organ Transplantation, University of Bari, 70124 Bari, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Cassano
authors.affiliation: Mariabeatrice Principi, Antonella Contaldo, Andrea Iannone, Giuseppe Losurdo, Michele Barone, Enzo Ierardi, Alfredo Di Leo, Gastroenterology Section, Department of Emergency and Organ Transplantation, University of Bari, 70124 Bari, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Contaldo
authors.affiliation: Mariabeatrice Principi, Antonella Contaldo, Andrea Iannone, Giuseppe Losurdo, Michele Barone, Enzo Ierardi, Alfredo Di Leo, Gastroenterology Section, Department of Emergency and Organ Transplantation, University of Bari, 70124 Bari, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Iannone
authors.affiliation: Mariabeatrice Principi, Antonella Contaldo, Andrea Iannone, Giuseppe Losurdo, Michele Barone, Enzo Ierardi, Alfredo Di Leo, Gastroenterology Section, Department of Emergency and Organ Transplantation, University of Bari, 70124 Bari, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Losurdo
authors.affiliation: Mariabeatrice Principi, Antonella Contaldo, Andrea Iannone, Giuseppe Losurdo, Michele Barone, Enzo Ierardi, Alfredo Di Leo, Gastroenterology Section, Department of Emergency and Organ Transplantation, University of Bari, 70124 Bari, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Barone
authors.affiliation: Mariabeatrice Principi, Antonella Contaldo, Andrea Iannone, Giuseppe Losurdo, Michele Barone, Enzo Ierardi, Alfredo Di Leo, Gastroenterology Section, Department of Emergency and Organ Transplantation, University of Bari, 70124 Bari, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Mastrolonardo
authors.affiliation: Mariabeatrice Principi, Antonella Contaldo, Andrea Iannone, Giuseppe Losurdo, Michele Barone, Enzo Ierardi, Alfredo Di Leo, Gastroenterology Section, Department of Emergency and Organ Transplantation, University of Bari, 70124 Bari, Italy.
authors.forename: Gino Antonio
authors.initials: GA
authors.lastname: Vena
authors.affiliation: Mariabeatrice Principi, Antonella Contaldo, Andrea Iannone, Giuseppe Losurdo, Michele Barone, Enzo Ierardi, Alfredo Di Leo, Gastroenterology Section, Department of Emergency and Organ Transplantation, University of Bari, 70124 Bari, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: Ierardi
authors.affiliation: Mariabeatrice Principi, Antonella Contaldo, Andrea Iannone, Giuseppe Losurdo, Michele Barone, Enzo Ierardi, Alfredo Di Leo, Gastroenterology Section, Department of Emergency and Organ Transplantation, University of Bari, 70124 Bari, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Di Leo
mesh_terms: D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D015897:Comorbidity; D020022:Genetic Predisposition to Disease; D016575:Hidradenitis / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology* / Q000276:immunology; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology* / Q000276:immunology; D008019:Life Style; D015995:Prevalence; D011379:Prognosis; D012307:Risk Factors
chemical_list: D000893:Anti-Inflammatory Agents; D007166:Immunosuppressive Agents
keywords: Crohn’s disease; Hydradenitis suppurativa; Immunosuppressant drugs; Inflammatory bowel disease; Intestinal microbiota; Skin microbiota; Ulcerative colitis