Management of HS is challenging since no single treatment provides consistently effective results, leaving patients with frequent relapses. New treatment options are actively being explored as a result. Dapsone is a sulfonamide drug that is being considered as a possible agent for treating HS due to its antimicrobial and anti-inflammatory properties. Dapsone is bacteriostatic in action by competing with para-aminobenzoic acid for the active site of dihydropteroate synthetase, preventing bacterial folic acid synthesis.13 Dapsone has several anti-inflammatory mechanisms of action. In addition to reducing pro-inflammatory cytokines, dapsone has specifically been shown to induce a dose-dependent suppression on TNF-alpha.14 Dapsone suppresses the generation of reactive oxygen species and neutrophil elastase release through a dose-dependent reduction of intracellular and extracellular superoxide due to inhibition of calcium-dependent functions of neutrophils.15 Since dapsone combines several qualities that address the pathogenesis of HS, it may be a promising treatment. With few studies, limited to case reports and two case-series, reporting the outcomes of dapsone treatment in HS, there is a need for more research into dapsone's effectiveness in HS. This study aims to evaluate the clinical outcomes of moderate-severe HS patients being treated with dapsone.
MATERIALS AND METHODS
This retrospective chart review evaluated HS patients being treated with dapsone over the past 10 years at Wake Forest Baptist Medical Center Department of Dermatology. After receiving Institutional Review Board approval, the Wake Forest Baptist Medical Center Translational Data Warehouse database was queried to identify all patients with a diagnosis of HS (ICD-10: L73.2) and treatment with dapsone within the past ten years. Patients who were only prescribed the topical form or patients who were prescribed dapsone for a reason unrelated to HS were excluded from the analysis. Disease severity at dapsone initiation was determined using Hurley staging. This staging system classifies HS into three Stages: Stage I: abscess formation, single or multiple, without sinus tracts and cicatrization; Stage II: recurrent abscesses with tract formation and cicatrization, single or multiple, widely separated lesions; Stage III: diffuse or non-diffuse involvement, or multiple interconnected tracts and abscesses across the entire area.16 Treatment outcome was determined by physicians' assessment of patients at scheduled follow-up visits and was classified as: "no change" if no improvement in the severity of symptoms was noted, "slight improvement" if minimal improvement was observed, "clinically significant improvement," if a large improvement was observed, and "deterioration" if clinical symptoms progressed during treatment.
RESULTS
A total of 19 patients who have received dapsone treatment for HS were identified (Table 1). Of these patients, 13 were female and 6 were male (Table 2). The mean age of the included patients was 42.7 (range: 17-59). All patients had moderate to severe disease, with two patients having moderate (Hurley Stage II) disease and a total of 17 patients classified as severe (Hurley Stage III; Table 3). Several patients had disease refractory to other forms of treatment (Table 1). Glucose-6-phosphate dehydrogenase (G6PD) levels were normal for all patients.
A total of nine patients received additional treatment with adalimumab (Table 3). Of these nine patients, six experienced slight improvement during the combined treatment. No change was observed for the other three patients.
All patients included in the study received dosages of dapsone varying from 25-100 mg/day (Table 1). Overall, a total of 3 patients had clinically significant improvement, 10 patients had slight improvement, 6 patients had no change in disease state, and zero patients had deterioration of disease status (Table 3). Of the three patients who showed clinically significant improvement, two of them received additional treatment with spironolactone 100 mg/day (patient 4) and doxycycline 200 mg/day (patient 15). Eight of the ten patients who had slight improvement and two of the six patients who had no change also received additional treatment. On average, the time to response was 2 months.
Treatment was well tolerated with the exception of four patients with nausea and fatigue being the most commonly reported adverse effects. The dose of dapsone for patient 1 was decreased from 150 mg/day to 100 mg/day after the patient experienced nausea at the higher dose. Treatment with rifampin (150 mg/day) was stopped for patient 3 after experiencing an ill-defined interaction with dapsone. Details about the specific reaction that took place was not documented in the medical records.
Eight patients received progressively increasing doses of dapsone. Increased dosing was beneficial for five of these patients, resulting in either clinically significant improvement or slight improvement.
A total of nine patients received additional treatment with adalimumab (Table 3). Of these nine patients, six experienced slight improvement during the combined treatment. No change was observed for the other three patients.
