Ultrasound In‐Depth Characterization and Staging of Hidradenitis Suppurativa

BACKGROUND The clinical diagnosis of fistulous tracts and recurrent fluid collections in hidradenitis suppurativa (HS) may be complex. Information on subclinical involvement and grading of severity may improve management. OBJECTIVE To study HS lesions and evaluate the relevance of adding ultrasound (US) to the clinical examination. METHODS AND MATERIALS We reviewed the sonograms of consecutive patients with HS from January 1, 2010 to May 31, 2012. The abnormalities observed in the US examinations were organized, classified, and integrated into a clinical‐sonographic scoring system (SOS‐HS), to stage the disease. RESULTS Thirty‐four patients with HS with a total of 142 lesional areas were evaluated. US findings included subclinical fluid collections in 76.4% of the patients, fistulous tracts in 29.4%, dermal pseudocysts in 70.6%, and widening of the hair follicles in 100%. Concordance with the clinical HS scoring performed by dermatologists showed a significant fair agreement (k = 0.30; p < .001); concordance of SOS‐HS with clinical scores was acceptable but significantly lower (k = 0.27; p = .02) because clinical scores consistently underestimated disease stage and severity. CONCLUSION US examination of HS lesions provides anatomic information that is clinically unavailable. HS is possible to stage sonographically.