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.