Beard folliculitis by <i>Klebsiella aerogenes</i> 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 <i>Klebsiella aerogenes</i>, a Gram-negative enteric bacillus increasingly implicated in beard folliculitis in MSM. Combined oral and topical antibiotic therapy targeting <i>K. aerogenes</i> achieved full resolution. Differential diagnosis included <i>tinea barbae</i> caused by <i>Trichophyton mentagrophytes</i> ITS genotype VII, an emerging sexually transmitted dermatophyte with similar demographics and presentation. This case adds to a growing number of reports linking <i>K. aerogenes</i> to folliculitis in MSM, underlines the importance of bacterial culture in recalcitrant folliculitis, and raises awareness of <i>K. aerogenes</i> as a potential sexually transmissible pathogen. Prolonged therapy and avoidance of possible environmental reservoirs such as hot tubs may be necessary to prevent recurrence.