Hailey-Hailey disease (HHD) is a chronic genodermatosis with recurrent vesicles and erosions mainly in the intertriginous areas. Hailey-Hailey disease severely affects patient quality of life. Standard treatments attempt to control the flares, but often do not result in long-term remission of the disease.

To describe outcomes of treatment with superficial radiotherapy (SR) for severe treatment-refractory HHD.

This retrospective case-series included 13 patients with severe HHD with a mean (SD) duration of 24 (14) years whose treatments with SR and follow-up were conducted at the Department of Dermatology at Bispebjerg University Hospital (Copenhagen, Denmark) from January 2015 to April 2021.

Patients were treated with SR (20 kilovolt; 8 fractions of 2 gray was equal to 1 cycle) with a total dose of 16 gray in each treatment cycle. Patients received 1 to 6 treatment cycles with 1 to 5 separate body areas treated in each cycle. Sixty-two separate body areas were treated with SR.

Complete long-term remission, defined as no relapse during follow-up of at least 12 months.

For the 13 participants (mean [SD] age, 52 [18] years; 8 women [62%]), 56 of 62 treated areas (90%) achieved long-term remission, and the mean (SD) follow-up was 32 (12) months for the successfully treated areas. Nine of 13 patients (69%) responded with complete remission of all treated areas after the first treatment cycle and an additional 3 patients experienced complete remission after the second SR cycle. One patient with partial remission in 1 of 2 treated skin areas experienced such an improvement in HHD that they chose to abstain from retreatment. The treatment was followed by severe inflammation lasting for up to 1 month followed by temporary slight hyperpigmentation of the treated areas. The average Dermatology Life Quality Index score before treatment with SR was 22 (the disease having extremely large effect on the patient's life) and decreased to an average of 3 (small effect on the patient's life) after treatment with SR.

The results of this case series suggest that treatment with SR was associated with remission in patients with severe HHD and may provide a long-term improvement of treated skin areas.