Radiotherapy for Refractory Hidradenitis Suppurativa

This is a prospective, non-randomized, split-body interventional study enrolling adults with moderate to severe hidradenitis suppurativa involving bilateral axillary disease of comparable severity. Each participant will receive radiotherapy to one axilla, while the contralateral axilla will serve as an untreated within-subject control. Radiotherapy will be delivered to a total dose of 45 Gy in 15 fractions (3 Gy per fraction), administered three times per week over approximately five weeks. Patients will continue stable background HS therapies during the study period. Dermatologic assessments, lesion counts, physician global assessment scores, and patient-reported outcomes will be collected at baseline, during treatment, and at 4 and 12 weeks following completion of radiotherapy. Long-term safety and disease outcomes will be assessed by chart review for up to two years post-treatment. An optional punch biopsy sub-study will evaluate histologic changes associated with treatment response.