Cantharidine

Highly toxic active ingredient of Lytta vesicatoria (formerly Cantharis vesicatoria), the so-called Spanish fly (see below oil beetle dermatitis from the beetle family). On healthy skin it comes to a severe inflammation with blistering. Scarless healing. Cantharidine is used topically in cantharide patches, in combination with other external agents (e.g. salicylic acid and/or podophylline) for the treatment of vulgar warts and mollusca contagiosa.

1. Torbeck R et al (2014) Cantharidine: a comprehensive review of the clinical literature. Dermatol Online J 20. pii: 13030/qt45r512w0.
2. Moye VA et al (2014) Safety of cantharidine: a retrospective review of cantharidine treatment in 405 children with molluscum contagiosum. Pediatric Dermatol 31:450-454.