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The Role of PDT in Acne

Acne can be treated with multiple modalities including topical and oral antibiotics, benzoyl peroxides, sulfur compounds, retinoids, and oral hormonal agents, such as birth control pills or antiandrogens. When acne fails to respond to conventional treatments, oral isotretinoin (Accutane), is a highly effective prescription medication with significant side effects. A safe and alternative treatment to oral isotretinoin for recalcitrant acne patients is Photodynamic treatment (PDT).

In PDT, a chemical reaction activated by a light source is used to selectively destroy tissue. PDT works in acne by the destruction of P.acnes (a bacteria found in the pilosebaceous glands that is at the root of acne lesions) and the direct thermal injury to the sebaceous glands. Photodynamic treatment can consist of:

blue or red light alone
ALA (Levulan) and blue or red light
ALA and IPL (Intense Pulse Light)
ALA and PDL (Pulse Dye Laser; i.e. Vbeam Perfecta)

P. acnes produces porphyrins which when activated by visible light (especially blue light or red light) can destroy the bacteria that causes acne. ALA (aminolevulinic acid; Levulan) is a solution that is applied on the skin and activated by a light source to cause a direct thermal injury to the sebaceous glands and destruction of P. acnes. The light source to activate ALA can be blue light, red light, intense pulse light (IPL) or pulse dye laser (PDL).

Blue LED light only treatment produces variable responses. This is usually given 2x/week for 4 weeks for a total of 8 sessions. Red light penetrates deeper but can cause more side effects and down time. ALA and blue light is more effective than blue light alone. The ALA solution is left on the skin for 1 hour then activated by a blue LED light for approximately 5 minutes.

ALA and IPL treatments are more effective with a 50-70% response rate. The treatments are performed q2weeks for 8 weeks, repeat in 4 weeks and 12 weeks. The solution is left on the skin for 30-60 minutes before activation with 1 pass of the IPL light source.

ALA and PDL (Pulse Dye Laser) have been shown to be the most effective PDT protocol for the treatment of acne. After incubating for 1 hour with ALA (Levulan), the long pulse dye laser (595nm; Vbeam Perfecta) is used to treat active acne lesions, red post-inflammatory changes and scars. Treatments are done at monthly intervals for 1-4 sessions. Generally, there can be 100% of acne clearance in 3 sessions with long term acne remission (up to 13 months). ALA and PDL also can target blood vessels and cause an anti-inflammatory effect and decrease erythematous acne lesions and scars. Side effects are mild, consisting of mild erythema for 1-2 days.

In conclusion, PDT is a safe and effective treatment for resistant acne. This treatment is also an excellent alternative to oral isotretinoin (Accutane).