Trichoscopy as a Tool to Evaluate Early Dissecting Cellulitis in Patients Affected by Hidradenitis Suppurativa: A Prospective Monocentric Observational Study.

Background: Dissecting cellulitis (DC) is a rare neutrophilic dermatosis that leads to cicatricial alopecia. Although DC and Hidradenitis suppurativa (HS) have similar characteristics, their association remains poorly understood.

Objectives: In this prospective observational study, we used trichoscopy to identify subclinical signs of DC in male patients aged 18 years or older, presenting with HS. The objective of this study was to use trichoscopy to identify subclinical signs of DC in patients with confirmed diagnosis of HS.

Method: In this prospective, monocentric, observational study, we used trichoscopy to identify subclinical signs of DC in male patients aged 18 years or older, presenting with HS for their initial visit at our HS outpatient clinic from February 1, 2022, to January 31, 2023.

Results: Of the 23 male patients with HS, 8 (35%) had subclinical trichoscopy findings consistent with DC. The most frequent location was the vertex (6/8), and the majority of patients had early/inflammatory trichoscopic signs of DC (5/8). Additionally, patients with trichoscopic findings consistent with DC had a higher Hurley stage and the International Hidradenitis Suppurativa Severity Score System (IHS4). Among the cases with trichoscopic findings compatible with DC, the majority (6/8) were classified as having a "follicular" HS according to the Canoui-Poitrine classification. Patients were treated according to European S1 guidelines on HS.

Conclusions: This is the first study to evaluate subclinical DC findings in HS patients using trichoscopy. Although the trichoscopic findings of DC are heterogeneous, the use of this non-invasive technique, in conjunction with clinical evaluation, can improve diagnostic accuracy and lead to earlier diagnosis. These findings suggest a potential association between HS and DC, indicating the need for further studies to evaluate this relationship.