Prevalence of hidradenitis suppurativa in patients with axial spondyloarthritis

Objectives

To determine the prevalence of hidradenitis suppurativa (HS) in patients with axial spondyloarthritis (AxSpA) and to describe clinical, laboratory, and radiographic characteristics of patients diagnosed with HS.

Patients and methods

We performed a cross-sectional study of a cohort of 265 patients with AxSpA in follow-up at a tertiary hospital. Patients were screened for HS using a questionnaire, with subsequent diagnostic confirmation by a dermatologist. We collected demographic, clinical, laboratory, and radiographic data. Patients were classified by diagnosis of HS. A descriptive analysis and comparison were performed for both groups.

Results

A total of 148 of the 265 patients (55.8%) completed the screening questionnaire. Screening was positive in 9 patients (6.1%), although the diagnosis of HS was confirmed in only 4 (2.7%). Three patients were diagnosed during the study, with a mean diagnostic delay of 14.25 years. All the patients had mild HS (Hurley stage I). When patients with and without HS were compared, the HS group had more smokers (75% vs 18%; p = 0.005), greater disease activity according to BASDAI (5.6 ± 2.3 vs 3.2 ± 2.1; p = 0.026), less structural damage according to the axial BASRI (1.5 ± 1.3 vs 5.5 ± 3.5; p < 0.018) and shorter time since diagnosis of AxSpA (14.7 ± 2.6 vs 27.8 ± 13.5 years; p = 0.001). No significant differences were found for the remaining variables studied.

Conclusion

This study suggests that prevalence of HS in patients with axSpA is higher than the one observed in general population. The knowledge of this association should encourage clinicians to inquire about symptoms of HS and actively search for lesions.