Point-of-care ultrasound in Hidradenitis Suppurativa: applications for diagnosis, staging, and treatment planning

Abstract Hidradenitis suppurativa (HS) is a chronic, inflammatory skin condition that impacts patients’ quality of life (QOL). Clinically, HS is characterized by inflammatory skin findings, including nodules and abscesses, which occur in intertriginous areas of skin. Despite an increased understanding of symptomatology and rapid advancement of treatment, HS has significant diagnostic delays. Superimposed bacterial infections, cosmetic scarring, and, rarely, squamous cell carcinoma arising in chronically inflamed lesional skin are complications that may occur after missed diagnoses. Late HS diagnoses are associated with increased treatment burden, comorbidity risk, and personal time needed for medical visits. Ultrasound (US) imaging has emerged as a valuable imaging modality for the detection and adjuvant treatment of HS. This paper reviews the current use of point-of-care ultrasound in HS, with a focus on its role in early detection, disease progression tracking, and procedural applications. High (15 MHz) and ultra-high frequency (48–70 MHz) US imaging can detect subclinical enlargement of hair follicles, potentially enabling earlier identification of HS in at-risk individuals. However, the clinical benefit of such earlier detection has yet to be established. Nodules, abscesses, sinus tracts (clinically synonymous with fistulas and most often visualized sonographically as tunnels) can be distinguished on ultrasound, supporting staging and severity assessment in selected patients. The Hidradenitis Suppurativa Activity (US-HSA) scoring system recommends utilizing US imaging to compare baseline and follow-up lesions. US can also support selected aspects of procedural HS care, including preoperative mapping for surgical planning, abscess drainage, and intralesional triamcinolone injection. Investigational applications, including deep learning–based image interpretation, smartphone-linked sonography, contrast-enhanced ultrasound, and elastography, are under early development but have not yet been validated for routine use. Important limitations, including operator dependency, training requirements, uncertain interobserver reproducibility, restricted device availability, absent cost-effectiveness data, and unclear clinical meaning of subclinical findings, should be weighed when integrating ultrasound into routine HS care.