Why rifampin (rifampicin) is a key component in the antibiotic treatment of hidradenitis suppurativa: a review of rifampin's effects on bacteria, bacterial biofilms, and the human immune system.

Combinations of rifampin and clindamycin or rifampin, metronidazole, and moxifloxcin have been reported as effective treatments for hidradenitis suppurativa (HS) Hurley Stage 1 and Hurley Stage 2.  Clinical trials suggest that for stage 1 and mild stage 2 HS, clindamycin 300 mg twice daily and rifampin 300 mg twice daily for 10 weeks can substantially abate HS in ~80% of cases and remit HS in ~50% of cases.  Another study notes use of rifampin-moxifloxacin-metronidazole given for 6 weeks, dosed as rifampin (10 mg/kg once daily), moxifloxacin (400 mg daily), and metronidazole (500 mg thrice daily) with the metronidazole stopped at week 6.   Rifampin and moxifloxacin were continued if the HS improved and side effects did not occur.  Using this triple antibiotic regimen remission occurred in 100% Hurley Stage 1, 80% Hurly Stage 2, and 16.7 % of Hurley Stage 3 HS.   The author typically gives HS clindamycin 300 mg and rifampin 300 mg, each twice daily, for 10 weeks and assesses if remission has occurred.  If the patient has not achieved remission the author continues the regimen as long as the patient's clinical status continues to improve without side effects.  The reasons why rifampin is so effective against HS have not been fully defined and might involve rifampin's (1) antibacterial effects (2) effects on bacterial biofilms (3) anti-inflammatory effects (4) effects against granulomas (5) and immunomodulatory effects on neutrophils.  It is notable that rifampin, although not first line, is an effective treatment for Clostridium difficile, a pathogen that arises during treatment with clindamycin.  Thus, rifampin enhances safety when rifampin and clindamycin are combined for the treatment of HS.