Photodynamic Therapy and Skin Appendage Disorders: A Review

Photodynamic therapy (PDT) is a noninvasive treatment that utilizes light treatment along with application of a photosen- sitizing agent. In dermatology, PDT is commonly used and approved for the treatment of oncological conditions such as actinic keratosis, Bowen disease and superficial basal cell carcinoma. In the last 2 decades however, PDT has also been used for the treatment of several nonneoplastic dermato- logical diseases. The present review summarizes published data on PDT application in skin appendage disorders. Our literature review shows that: (a) PDT may be a suitable treat- ment for acne, folliculitis decalvans, hidradenitis suppurati- va, nail diseases, and sebaceous hyperplasia; (b) there is a lack of agreement on PDT features (type, concentrations and incubation period of used substances, number and frequen- cy of PDT sessions, optimal parameters of light sources, and patient characteristics [e.g., failure to previous treatments, disease severity, body surface area involved, etc.] which should guide PDT use in these diseases); (c) further research is needed to establish international guidelines helping der- matologists to choose PDT for the right patient at the right time.