Ultrasonography of Facial and Submandibular Hidradenitis Suppurativa and Concomitance With Acne Vulgaris

Objectives To describe the ultrasound characteristics of facial and submandibular hidradenitis suppurativa (HS) and detect acne vulgaris (AV) concomitance in these cases. Methods We performed a retrospective study of the ultrasound images of patients with facial HS who had been clinically evaluated by dermatologists. The reported ultrasound diagnostic criteria, severity (mSOS‐HS), and activity (US‐HAS) staging of HS were used to categorize the patients. The finding of fragments of hair tracts within the key lesions (dilated hair follicles, pseudocysts, fluid collections, and tunnels) was considered a pivotal sign to discriminate HS from AV. Demographic and morphological analysis of the images were considered. Results Thirty‐three patients met the criteria (78.8% male/21.2% female). Of these, the mSOS‐ HS scoring was stage I in 51.5%, stage II in 27.3%, and stage III in 21.2%. Dilation of the hair follicles and the presence of pseudocysts, fluid collections, and tunnels were detected in the HS cases; 63.1% of pseudocysts, 62.4% of tunnels, and 46.2% of fluid collections contained fragments of hair tracts. In all HS cases, there was a key lesion(s) with fragments of hair tracts. Four (12.1%) patients showed concomitant facial HS and acne ultrasound lesions. The acne lesions were pseudocysts without inner hair tract fragments in all cases, and the SOS‐Acne scoring was stage II for all of them. Conclusion Facial HS can be detected on ultrasound and shows a morphology similar to that of HS in other corporal regions. In some cases, facial HS could be concomitant with AV. The subclinical ultrasonographic information can support a better management of these cases.