Study aimed to evaluate efficacy of HBOT as an adjunctive therapy in patients with HS receiving systemic rifampicin and clindamycin. Groups were comparable with respect to age, BMI, gender, and smoking habits. ESR and CRP levels were gathered at baseline and at 4 and 10 wks of treatment. Patients in the HBOT group showed a decreased from baseline parameters including CRP (72.7%). Adjunctive HBOT significantly improved antibiotic treatment of HS. The gene discussed is ESR1; the disease is histiocytic sarcoma.