The application of PDT as a modality for nonablative photorejuvenation is an extension of its efficacy in treating actinic damage and photoaging (for review, see Alexiades – Armenakas) [39]. The application of topical ALA for short incubation times, combined with newer laser and light sources has been shown to be safe and effective for the […]

Topical ALA PDT with short incubation and activation by various light sources includ­ing blue and red wavelengths, LP PDL, and IPL is emerging as a safe and effective treat­ment option for acne patients. In Table 21.1, several published treatment methodologies are presented using topical ALA, and the most effective and commonly used light sources. Although […]

The data from several published studies indicate that the mechanism of PDT in treating acne lesions is through the targeting of sebaceous gland activity, as is the case for many effective acne treatments. Hormonal activation of the pilosebaceous unit results in hyper – cornification, sebum production, and proliferation of P acnes. Among the hormones impli­cated […]

Among the Q bands in the PPIX absorption spectrum, a peak at 575 nm is amenable to activation through PDL [21]. PDL (585 nm) following topical 20% ALA was used for the treatment of AK, but with purpura and crusting (see Photoaging) [22]. LP PDL (595 nm) following short incubation ALA was shown to be […]

Topical ALA and blue light (peak 417 nm) has yielded more modest efficacy in reported studies, likely due to the shallower penetration depth of these shorter wavelengths. In one study, blue light therapy once weekly for 2 weeks resulted in 25% improvement for light alone, and 32% improvement following ALA application prior to illumination [9]. […]

Topical ALA application has also been shown to result in PpIX fluorescence at a higher level within acne lesions than in surrounding normal skin [15]. Subsequent exposure to red light was shown to shrink sebaceous glands [15]. Topical ALA for 3-hour incubation under occlusion followed by red broad-band light (550-700 nm) yielded significant improvement in […]

The porphyrins produced by P acnes in the sebaceous follicle are in small quantities, and exogenous ALA has been shown to concentrate in sebaceous units [13]. Intraperitoneal injection of ALA into albino mice was shown to result in the accumulation of protoporphy­rin IX (PpIX) in the sebaceous glands of normal skin such that exposure to […]

Light alone can activate the PDT reaction by stimulating porphyrins which accumulate within the sebaceous follicle in acne. Porphyrins, mainly coproporphyrin III, are produced by Propionibacterium acnes, the anaerobic bacterium that proliferates and causes inflam­mation in obstructed sebaceous follicles [7]. Endogenous porphyrins serve as photophores to mediate the PDT reaction following exposure to light, particularly […]

21.1.1 Background Laser and light treatments for acne have included the FDA-approved blue light and diode 1450 nm laser, both of which act by targeting the sebaceous glands [3]. The disadvantages of these treatments are that they require multiple treatments and are modestly effective, with recurrences being relatively common [3]. The recent strict regulation of […]