Delayed skin test reactivity to Propionibacterium acnes correlates with severity of inflammation in acne vulgaris

Abstract

P. acnes is the bacterial species most consistently isolated from acne lesions. Intradermal injection of a heat-killed suspension of P. acnes induced a delayed erythematous and often papular inflammatory reaction which was maximal after 24-48 h. This response was dose-related and was probably mediated at least partly by immune mechanisms. In 81 [human] subjects with acne of varying severity, the intensity of the 48-h skin test reaction was significantly related to the severity of the acne. The host response to P. acnes apparently is an important variable in determining the severity of inflammatory acne.