High- and Ultra-High-Frequency Ultrasound Identifies a Subclinical Link Between Suppurative Comedonal Nevus and Hidradenitis Suppurativa.

Suppurative nevus comedonicus (SNC) is a variant of nevus comedonicus in which the characteristic features coexist with recurrent inflammatory lesions that clinically resemble those of hidradenitis suppurativa (HS). We present the ultrasound characteristics of this entity and emphasize the value of high-resolution dermatologic ultrasound both as a diagnostic tool and for detailed lesion assessment in SNC. A retrospective, descriptive cross-sectional study was performed in patients with a clinical diagnosis of nevus comedonicus. Clinical and sonographic information was collected. All participants underwent ultrasound evaluation of the affected area, the contralateral region, and additional anatomical sites commonly involved in HS. Examinations were carried out using color Doppler ultrasound with high-frequency probes (18 and 24 MHz) and an ultra-high-frequency 71 MHz transducer. Severity was staged ultrasonographically in all patients using the mSOS-HS classification. Six patients met the inclusion criteria. In every case, ultrasound demonstrated features analogous to those typically observed in HS within the examined zones. However, in contrast to HS, clinical SNC lesions consistently followed a linear or segmental pattern and were exclusively unilateral. Ultrasonographic findings included follicular dilatations, pseudocysts, tunnels, dermal and subcutaneous inflammatory collections, and reduced dermal echogenicity accompanied by signs of local inflammation (hypervascularity). Overall, the ultrasound characteristics of SNC mirror a localized, segmental form of HS occurring in non-typical HS locations, strongly supporting a potential etiological link between the 2 disorders. This imaging information, not previously reported, may contribute to a better understanding of both conditions and aid in optimizing patient management.