Beard folliculitis by Klebsiella aerogenes in a young man: An emergent sexually transmitted infection?

Beard folliculitis is a frequent dermatologic complaint, but uncommon pathogens may challenge diagnosis and treatment. We report a case of persistent beard folliculitis in a 23-year-old man who has sex with men (MSM), unresponsive to conventional therapies. Culture of a pustule identified Klebsiella aerogenes, a Gram-negative enteric bacillus increasingly implicated in beard folliculitis in MSM. Combined oral and topical antibiotic therapy targeting K. aerogenes achieved full resolution. Differential diagnosis included tinea barbae caused by Trichophyton mentagrophytes ITS genotype VII, an emerging sexually transmitted dermatophyte with similar demographics and presentation. This case adds to a growing number of reports linking K. aerogenes to folliculitis in MSM, underlines the importance of bacterial culture in recalcitrant folliculitis, and raises awareness of K. aerogenes as a potential sexually transmissible pathogen. Prolonged therapy and avoidance of possible environmental reservoirs such as hot tubs may be necessary to prevent recurrence.