Photodynamic therapy in acne: can we achieve therapeutic gain without pain?

Conflicts of interest C.A.M. has acted as an adviser, lecturer and/or researcher for Galderma, Janssen and Leo Pharma. Impressive response rates have been observed following the use of topical photodynamic therapy (PDT) in acne, but the treatment remains little used in practice compared with its established indications in nonmelanoma skin cancer. Why? Therapy‐induced pain, erythema, sterile pustular reactions and hyperpigmentation, as well as the need for multiple treatments, have so far limited patient enthusiasm for PDT in acne. PDT, the interaction of a photosensitizer, light and oxygen to promote a targeted therapeutic effect, can promote improvement in acne via antibacterial activity against Propionibacterium acnes, as well as selective damage to sebaceous glands, reduction in follicular obstruction by keratinocyte shedding and via secondary host responses.1Propionibacterium acnes naturally produces small amounts of certain porphyrins, especially coproporphyrin III, hence the beneficial effects observed in light‐only studies, but application of an additional exogenous photosensitizer is necessary to maximize the effect of PDT in acne, facilitating its use even in moderate‐to‐severe disease.