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Treatment-related changes in hyperpigmentation are difficult to quantify with visible light photography, especially when the changes are subtle.Our purpose was to determine the utility and reliability of fluorescence photography to measure changes in mottled and diffuse hyperpigmentation.Thirty-two subjects, with mildly to moderately photodamaged skin, completed a 36-week, double-blind, vehicle-controlled study of tretinoin cream 0.025%. Clinical evaluation of hyperpigmentation as well as standard flash photographs and fluorescence photographs were obtained at baseline and week 36.The fluorescence photographs were evaluated blindly and yielded macule counts that decreased significantly from baseline in tretinoin-treated subjects compared with vehicle-treated subjects (31% vs 11% decrease; p = 0.02). Diffuse hyperpigmentation, as evaluated from the fluorescence photographs, decreased 16% from baseline for tretinoin-treated subjects and increased 5% for vehicle-treated subjects (p0.01). No significant differences in mottled or diffuse hyperpigmentation were observed between groups through clinical evaluation.Fluorescence photography is a noninvasive method that is sensitive in the evaluation and quantification of distribution and changes of mottled and diffuse hyperpigmentation.

Chronic exposure to a weak irritant leads to inflammatory changes which may be followed by pigmentary changes and accommodation. The inflammatory responses to acute exposure to an irritant have been extensively studied. This study investigated quantitatively the inflammatory reactions produced in photodamaged skin with chronic application of a weak chemical irritant (tretinoin cream 0.025%) over a period of 9 months (36 weeks). Forty-eight subjects with moderately to severely photodamaged skin were enrolled in a 36-week, double-blind placebo-controlled study. Tretinoin cream was applied nightly on the distal two thirds of one dorsal forearm and placebo on the other. The proximal third of each dorsal forearm received no treatment and served as control. Clinical assessments and diffuse reflectance measurements were made at 7 time points during treatment. Apparent concentrations of oxyhemoglobin (HbO2), deoxyhemoglo-bin (Hb) and melanin were estimated by analysis of the diffuse reflectance spectra. No changes were observed in the apparent H bO2or the Hb concentration of the placebo-treated or control sites, thus establishing a reliable baseline. The apparent HbO2 concentration of the tretinoin-treated sites increased significantly from baseline to a maximum at 12-18 weeks of treatment, then returned to baseline with continued applications. The changes in HbO2 concentration agreed closely with clinical assessments of erythema. The apparent melanin concentration, corresponding to diffuse hyperpigmentation, showed a large seasonal decrease in both the control and the treated sites, with an additional decrease in the treated sites between 12 and 18 weeks. Erythema appeared after repeated applications and eventually resolved under continuous treatment. The maximum decrease in hyperpigmentation occurred simultaneously with the maximum increase in erythema.

Background: Quantification of acne remains a challenge. It may be difficult to identify lesions by standard flash photography. Previous studies have shown that foci of light in fluorescence photographs correspond to high protoporphyrin IX production by Propionibacterium acnes in open comedones, follicles, and inflammatory lesions. Objective: Our purpose was to study the utility of fluorescence photography for evaluation of acne. Methods: Forty subjects with mild to moderate acne vulgaris were randomly selected to apply either clindamycin 1% topical solution or vehicle twice daily. Counts of acne lesions and flash and fluorescence photographs were obtained at baseline, and at 4, 8, and 12 weeks. Results: At 12 weeks, the treatment group had a larger percentage change in open comedones, less fluorescence in all areas assessed, and a larger percent decrease in fluorescence than the vehicle group. Conclusion: Fluorescence photography appears to be a useful tool to chart the course of acne treatment.