Characterization of Hidradenitis Suppurativa Phenotypes: A Multidimensional Latent Class Analysis of the National Italian Registry IRHIS.

In spite of the large heterogeneity, limited data exist on hidradenitis suppurativa (HS) phenotypes. To identify the HS phenotypes that best explain the disease heterogeneity, a cross-sectional study using latent class (LC) analysis was conducted on a cohort of patients examined at 17 dermatological centers participating in the Italian Registry of Hidradenitis Suppurativa and being enrolled between January 2015 and January 2020. Overall, 965 patients aged 32.0 ± 12.4 years (mean ± SD) were evaluated. A three-class model in LC analysis best fitted the data. Patients in LC1 (20.1%) were females, mostly obese, with a high probability of axillary‒groin (0.85) and mammary (0.59) lesions and the highest HS severity. Patients in LC2 (29.6%) were nonobese males, with moderate disease severity; with a high probability of gluteal (0.50) and genital (0.17) lesions, besides axillary‒groin involvement; and with acne and pilonidal cysts. Patients in LC3 (50%) were nonobese females with a milder disease mostly limited to axillary (0.52) and groin (0.66) areas. The stratification of patients with HS into a severe axillary‒mammary‒groin phenotype with predominantly anterior body involvement in females, an axillary‒gluteal‒groin phenotype of intermediate severity mainly affecting males in the posterior body areas, and an axillary‒groin phenotype with mildest clinical symptoms and limited skin involvement may help in optimizing HS management.