 Decreased levels of retinoic acid in the skin may contribute to comedone formation. To address this deficiency, and potentially replace the use of irritating topical retinoids, methods to increase the skin's production of retinoid acid are being explored. A vaccine against inflammatory acne has been tested successfully in mice, but has not yet been proven to be effective in humans. Other workers have voiced concerns related to creating a vaccine designed to neutralize a stable community of normal skin bacteria that is known to protect the skin from colonization by more harmful microorganisms.
