Comorbidities and mortality of hidradenitis suppurativa in Finland

Thesis event information

Date and time of the thesis defence

Place of the thesis defence

Oulu University Hospital, Auditorium 8

Topic of the dissertation

Comorbidities and mortality of hidradenitis suppurativa in Finland

Doctoral candidate

Licentiate of medicine, Specialist in dermatology and allergology Hannu Tiri

Faculty and unit

University of Oulu Graduate School, Faculty of Medicine, PEDEGO Research Unit

Subject of study



Professor emerita Erna Snellman, Satasairaala


Professor Kaisa Tasanen-Määttä, University of Oulu

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Patients with hidradenitis suppurativa have an increased risk for several diseases

Hidradenitis suppurativa (HS) is a chronic inflammatory disease of hair follicles. HS typically manifests as recurrent and painful lumps and boils in the skin of the armpits, groin, buttocks, and genital area. These lesions may rupture and drain through multiple openings. With time, persistent tunnel-like tracts with discharge, and thick scars usually form. HS is difficult to treat and has a profound negative impact on the quality of life.

The aim of this thesis work was to investigate comorbidities and mortality in HS patients in a nationwide retrospective case-control setting. Information on other diseases of patients with HS (more than 4,300 patients) was obtained from the Care Register for Health Care maintained by the Finnish Institute for Health and Welfare. Patients with HS were compared with those treated for psoriasis or melanocytic nevi in specialized medical care. Mortality data on deceased subjects were obtained from Statistics Finland.

In this study, HS patients showed a significantly heightened risk of psychiatric disorders in adulthood and even before the age of 18 years. In addition, the risks of many somatic diseases, such as inflammatory bowel and joint diseases, were increased in children with HS. Furthermore, HS patients were found to die considerably younger than the controls, and an elevated risk of suicide was observed in women with HS. Based on this thesis work, HS patients have a high burden of psychiatric disorders. When treating patients with HS, the risk of both somatic and psychiatric comorbidities needs to be kept in mind. Comprehensive and multidisciplinary care is required to improve these patients’ quality of life and to prevent their untimely death.
Last updated: 1.3.2023