PDT is thought to treat acne by two primary mechanisms. First, it shrinks the skin’s oil glands (sebaceous glands) that contribute to acne formation. This can drastically reduce the amount of oil within the pores, thereby reducing comedones (blackheads and whiteheads). Second, PDT also kills the bacteria (Propionibacterium acnes) that live on facial skin and cause acne breakouts. In addition, PDT seems to improve the skin’s overall texture, and may speed the resolution of acne-induced discoloration (red or dark spots that remain after the pimples have resolved).
First, excess dead cells on the skin’s surface are removed using an acetone scrub. This enhances the penetration of the photosensitizing agent. Next, the photosensitizing agent (Levulan) is applied to the skin and allowed to incubate for a period of 15 to 60 minutes. The agent is then removed and the skin is treated with light for about 15 minutes. Many patients report feeling moderate warmth during the procedure but most do not feel any pain. Patients must avoid sun exposure for 2 days after the treatment.
A series of 4 to 6 treatments are usually performed at 1 to 2 week intervals. The number of treatments recommended depends on the severity of acne. Some patients may notice results after the first treatment.
The majority of patients report significant improvements ranging from a 50% to 75% reduction in acne lesions after a few treatments. However, a small amount of patients show only modest improvements and results vary for each individual patient. For some patients the results can be permanent, others require touch-up treatments a few times a year. Some patients do not respond well to this treatment so other modalities are needed. While results are not guaranteed, the majority of patients are very satisfied with treatment.
The side effects of PDT may include redness and/or peeling of the treatment site. Patients have described it as being similar to a sunburn. It is generally mild and resolves in 1 to 8 days.
The cost for the entire procedure is not covered by insurance but is affordable in comparison to some acne medications. Most patients require series of treatments to achieve optimal results.