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 (p < 0.05), but not with SOS-HS severity. Comorbidities correlated with disease duration (r = 0.256, p = 0.01), and the follicular-furunculous phenotype was associated with the females (p = 0.04). Clinical and ultrasound assessments showed strong correlations, although ultrasound showed higher severity scores (r = 0.42 to 0.92, p < 0.05), as well as significant differences across the phenotypes.

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.