Prevalence of Hidradenitis Suppurativa in Brussels, Belgium: Validation of a Screening Questionnaire.

Background: Hidradenitis suppurativa (HS) is a chronic, inflammatory, recurrent and debilitating skin disease, with a poorly understood global burden. The prevalence of HS in Belgium is not yet known. We aimed to determine the prevalence of the disease in the Belgian context and validate a screening questionnaire.

Materials and methods: Conducted as part of the Global Hidradenitis Suppurativa Atlas (GHiSA) initiative, this monocenter cross-sectional study involved 500 healthy adults accompanying patients at the Erasme Hospital in Brussels. Participants gave their consent and completed a screening questionnaire. All screen-positive and a subset of some screen-negative participants underwent clinical examination by a dermatologist. The severity of the disease was assessed using the Hurley staging.

Results: The prevalence of HS in the sample was 1.6% (8/500; 95% Cl: 0.81%-3.13%). There were no statistically significant demographic differences between the group control and the HS group. The screening questionnaire demonstrated a sensitivity of 100%, a specificity of 89%, a positive predictive value of 56% and a negative predictive value of 100%. Most of the patients diagnosed with HS were Hurley I (6/8) and the axilla was the most affected area.

Conclusion: The study uncovered a 1.6% prevalence of HS among a cohort of 500 Belgian participants and contributed to the GHiSA project. The high sensitivity and specificity of the screening questionnaire suggests it is an effective tool for detecting HS in the general population.