SG15 Unravelling the risk factors for hidradenitis suppurativa: a genetic approach

Abstract Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition marked by recurrent abscesses, painful nodules and scarring, affecting areas such as the axillae, groin and anogenital regions. Its prevalence varies globally, with higher rates observed in Europe than in the USA and Asia–Pacific regions (Phan K, Charlton O, Smith SD. Global prevalence of hidradenitis suppurativa and geographical variation – systematic review and meta-analysis. Biomed Dermatol 2020; 4: 2). Genetic factors are crucial in HS susceptibility, with heritability estimated at 80%, primarily due to gene–gene interactions (Kjærsgaard Andersen R, Clemmensen SB, Larsen LA et al. Evidence of gene–gene interaction in hidradenitis suppurativa: a nationwide registry study of Danish twins. Br J Dermatol 2022; 186: 78–85). The disease is associated with a variety of comorbidities, including obesity, cardiovascular risk factors, smoking and inflammatory bowel disease (Shlyankevich J, Chen AJ, Kim GE, Kimball AB. Hidradenitis suppurativa is a systemic disease with substantial comorbidity burden: a chart-verified case–control analysis. J Am Acad Dermatol 2014; 71: 1144–50). This study aims to explore the causal relationships between modifiable risk factors, comorbid diseases and HS using a two-sample Mendelian randomization approach. We analysed genetic variants linked to behavioural and disease-related risk factors, including body mass index (BMI), education, smoking, alcohol consumption, acne, atopic dermatitis, Crohn disease, psoriasis and systemic lupus erythematosus. The results show a significant association between higher BMI and HS risk (odds ratio 1.19 per 1-SD increase), as well as an inverse relationship between education and HS (odds ratio 0.81 per additional year of education). Acne, atopic dermatitis and Crohn disease were notably associated with increased HS risk. However, smoking and alcohol consumption exhibited weaker and inconsistent associations. These findings highlight the role of both genetic and environmental factors in the pathogenesis of HS and suggest potential areas for intervention, including weight management, improved healthcare access and addressing comorbid conditions. Future research should further explore the shared inflammatory mechanisms between HS and its comorbidities to improve understanding and treatment strategies for this debilitating disease.