Azithromycin Treatment for Acne Vulgaris: A Case Report on the Risk of Clostridioides difficile Infection.

BACKGROUND Clostridium difficile (C. difficile) is a gram-positive, anaerobic, spore-forming bacillus. It can lead to pseudomembranous colitis characterized by electrolyte disturbances, toxic megacolon, and septic shock. The risk of C. difficile infection is higher with use of certain classes of antibiotics, or when an antibiotic used for a long time. Azithromycin is a macrolide antibiotic known to be safe, with few adverse effects such as diarrhea, stomach pain, and constipation. Azithromycin is currently used for the treatment of acne, with different dosing regimens for patients who cannot receive traditional treatment based on practice guidelines. CASE REPORT A 41-year-old woman was treated with a course of azithromycin 500 mg by mouth 3 times weekly for 6 weeks for acne vulgaris. This was her second antibiotic course of acne treatment within 10 months. A few days after completion of the second azithromycin course, she presented to the clinic with worsening abdominal pain and frequent soft bloody stool. A complete blood count test, C. difficile toxin test, stool culture, and colonoscopy were ordered. She was diagnosed with C. difficile infection confirmed by C. difficile toxin and symptoms. CONCLUSIONS Despite the safety profile of azithromycin, our patient was predisposed to a non-severe case of C. difficile-associated diarrhea, most likely due to the repeated course of the azithromycin regimen that was used to treat her acne vulgaris. This report highlights the importance of managing patients with acne vulgaris according to current practice guidelines, and to report a link between the use of azithromycin as an acne treatment and the occurrence of C. difficile colitis.