Background: Hidradenitis suppurativa (HS) is an inflammatory skin disease with a chronic intermittent course. HS is difficult to treat, and the evidence for the effect of most treatments consists of smaller open studies. The use of dapsone in the treatment of HS is based on a few published cases successfully treated. Objective: To evaluate the potential of dapsone treatment for HS in an open case series. Methods: An exploratory and retrospective review of case notes from HS patients treated with dapsone was performed. Patients were included irrespective of treatment outcome. Prior to the treatment the level of glucose-6-phosphate dehydrogenase in the blood was tested for all patients. Results: A total of 24 HS patients were included and treated with dapsone. Improvement was seen in 9 out of 24 (38%) treated patients, whereas 15 out of 24 (62%) did not experience any improvement. None of the 4 cases with severe disease experienced improvement. Side effects leading to discontinuation of the treatment occurred in 2 of 24 patients (8%). Recurrence of disease at the cessation of treatment was described as rapid. Limitations: The study is limited by lacking a control group. Conclusion: Therapy with dapsone for patients with HS is possible, particularly in milder cases. The effect may be due to either antibacterial or anti-inflammatory effects of the drug, or both. Rapid recurrence after stopping treatment however suggests that anti-inflammatory effects may predominate. The effect appears to be smaller than that reported with combination therapy using clindamycin and rifampicin. To clarify the true effect of dapsone future randomized controlled trials are necessary.