Abstract
Despite multiple possible side effects, mesotherapy with a diverse mixture of unapproved products has been performed for the treatment of hair loss. In this case report, we present a rare case of permanent hair loss due to an allergic reaction from a mesotherapy mixture including triamcinolone acetonide. The patient showed a positive intradermal allergic skin test result for triamcinolone and therefore was diagnosed with scarring alopecia due to delayed type IV hypersensitivity to corticosteroid. This case study suggests that dermatologists should always be fully aware that both IgE-mediated and non-IgE-mediated hypersensitivity reactions from the corticosteroids as well as their mesotherapy excipients are possible in an effort to prevent irreversible adverse event from the mesotherapy.