Supplementary Material for: Intralesional Triamcinolone for Fistulous Tracts in Hidradenitis Suppurativa: An Uncontrolled Prospective Trial with Clinical and Ultrasonographic Follow-Up

<b><i>Background:</i></b> There is little evidence on the use of intralesional triamcinolone (ILT) for managing fistulous tracts in hidradenitis suppurativa (HS). <b><i>Objective:</i></b> To assess the clinical and ultrasound response to ILT for single fistulous lesions in HS patients. <b><i>Methods:</i></b> A prospective open-label study was conducted to assess response to ILT (40 mg/mL) for fistulous tracts in HS. Consecutive patients (Hurley II stage exclusively) presenting to our department were recruited from August 2016 to August 2018. They received a single injection of ILT as the sole treatment. Lesions were assessed clinically and by ultrasound at baseline and 90 days. <b><i>Results:</i></b> Of the 53 included HS patients with fistulous tracts, 36 (67.9%) were women, 30 (56.6%) were smokers, and 36 (67.9%) were obese or overweight (body mass index ≥25). Median Sartorius score was 9.0 (IQR 9.0–36.0), and median duration of the lesion treated was 6 months (IQR 3.0–12.0). Fistulous tracts were injected with 0.5 mL triamcinolone 40 mg/mL. Seven patients were lost to follow-up. At 90 days, 20 (43.5%) lesions showed clinical and ultrasound resolution, 13 (28.3%) showed only clinical resolution while persisting on ultrasound, and 13 (28.3%) persisted both clinically and on ultrasound. Mean clinical size decreased from 17.0 to 5.1 mm (<i>p</i> < 0.0001), while mean length on ultrasound decreased from 16.0 to 8.6 mm (<i>p</i> < 0.0001). <b><i>Limitations:</i></b> Small sample size and no control group. <b><i>Conclusions:</i></b> Our study suggests that ILT is beneficial for small fistulous tracts in HS.