High-frequency ultrasound in the diagnosis of Hidradenitis suppurativa: experience from the Bulgarian HS Expert Centre.

Introduction: Hidradenitis suppurativa (HS) is an immune-mediated, autoinflammatory skin disease with different clinical manifestations. Traditional clinical examination may not assess HS true extent, while high-frequency ultrasound can detect subclinical lesions, influencing severity assessments. Aim: To compare the clinical severity of HS with the ultrasonography-based staging, and explore relationships between demographic data, risk factors and clinical phenotypes. Material and methods: An ongoing pilot study included 98 patients of the Bulgarian HS Expert Centre. Informed consent and epidemiological data were collected. Patients were categorized into disease duration groups (short/long) and classified by phenotype. Clinical severity was assessed through Hurley, IHS4, and HS-PGA staging systems and by ultrasound using SOS-HS, US IHS4, and US HS-PGA scales. Results: The study cohort was predominately male (74.5%) with a mean age of 36.69 years, average disease duration of 7.6 years and prevalence of the regular phenotype (53%). Age and disease duration correlated with Hurley stage ( Conclusions: HS is often underestimated due to delayed diagnosis and atypical presentations. Combining clinical and ultrasound assessments can provide more accurate staging. A multidisciplinary approach in expert centres can enhance diagnosis, treatment and monitoring.