Biologic agents are becoming increasingly used in the treatment of many systemic inflammatory diseases. Despite their good safety profile, they can cause some side effects including paradoxical adverse events (PAEs). One of the possible PAEs of biologic treatment is granuloma annulare (GA).GA is a chronic granulomatous inflammatory skin disease, manifested by circularly arranged papules, usually located on the dorsal surfaces of extremities, but can appear on any site of the body. In Complete resolutionAbbreviations: NMO, neuromyelitis optica; PS, psoriasis; PsA, psoriatic arthritis; RA, rheumatoid arthritis.

Introduction: Hidradenitis suppurativa is a chronic inflammatory skin disease with a typical formation of inflamed nodules, abscesses, and sinus tracts usually in the axillary, inguinal, and anogenital region. We decided to investigate the possible association of hidradenitis suppurativa and total IgE elevation and to explore the patients’ characteristics which can be related to high IgE levels. Methods: We performed a retrospective observational study which included 67 patients with moderate-to-severe stage of hidradenitis suppurativa followed up in our outpatient dermatology department. Total IgE, IgA, IgG, IgM, and CRP serum levels were measured. A personal and family history was taken. We asked them about allergic diseases and cigarette smoking and determined the basic parameters such as the weight and height of the patients. Results: Elevated total IgE levels were noticed in 21 patients (31.3%), of which 6 had a history of allergic disorder. Three of them had allergic rhinoconjunctivitis and the other three were suffering from atopic dermatitis. The mean total IgE level was 203.0 IU/ml with a maximum value of 1,954 IU/ml. Analysis of the factors, such as cigarette smoking, sex, elevated CRP, body mass index, and the number of affected areas, did not show an association with increased IgE levels. Conclusion: Our study showed a higher mean value of total IgE in patients with moderate to severe hidradenitis suppurativa than in the general population. However, we did not confirm an association with any characteristics of the patients. Limitations of this work include a small number of patients and a lack of the control group, therefore further and more extensive studies are needed to support these results.

Summary: Introduction: Association between hidradenitis suppurativa (HS) and chronic inflammatory bowel disease (IBD) exists. Prevalence of IBD in patients with HS is not clear. The aim of this paper is to determine the prevalence of IBD in patients with HS, evaluate risk factors and possible phenotype of patients with HS and IBD. Methods: Single center retrospective analysis of 241 patients with HS was carried out and medical files were searched for inflammatory bowel disease accordingly. Epidemiologic data of HS were collected. Results: IBD had a prevalence of 5.8%. Out of this number 13 (92.9%) suffered from Crohn’s disease (CD) and 1 (7.1%) from ulcerative colitis (UC). Eight patients (57.1%) were referred to the dermatologist by gastroenterologist and in six patients (42.9%) history of IBD was detected by dermatologist during routine examination. Special phenotype of the disease associated with IBD was not confirmed. The study points out possible existence of common comorbidities and risk factors such as smoking and obesity. Discussion: Our study confirmed similar data like those available in literature, where strong association between CD and HS is present and weaker with UC and HS. Conclusion: The prevalence of IBD in HS patients (5.8%) however these patients do not have a distinct HS phenotype. Key words: hidradenitis suppurativa – chronic inflammatory bowel disease – Crohn’s disease – ulcerative colitis – comorbidities – association – risk factors