Introduction: Chronic exposure to ultraviolet radiation is the primary cause of skin carcinomas. Actinic keratosis is considered a precursor lesion. Topical application of photolyase showed effectiveness with the removal of 40-45% of the dimers formed by ultraviolet radiation, contrasting with conventional photoprotection for its ability to repair already damaged cellular DNA. Confocal microscopy is used for the in vivo visualization of skin alterations. Objective: To evaluate the effects of the cream containing photolyase and SPF 100 sunscreen on facial actinic damage and keratoses, using dermoscopy and confocal microscopy as evaluation parameters. Methods: Observational longitudinal clinical trial in 17 actinic keratosis lesions. Dermatoscopy and confocal microscopy were carried out before applying the cream and 120 days after, with comparison of the images. Results: Of the 14 Grade I actinic keratoses, nine showed clinical and dermoscopic improvement, three remained unchanged and one progressed to Grade II actinic keratosis. Confocal microscopy showed a reduction of scales and improvement in the epidermal architecture in the five Grade I actinic keratoses. The three Grade II actinic keratoses analyzed did not show improvement. Conclusions: The application of photolyase in cream with sunscreen promotes photoprotection and DNA repair. Confocal microscopy is a useful tool for monitoring the treatment of actinic keratoses.

Keywords: KERATOSIS, ACTINIC; MICROSCOPY, CONFOCAL; DERMOSCOPY.

INTRODUCTION: Actinic keratosis (AK) is a pre-malignant lesion that can progress to squamous cell carcinoma. The diagnosis is through clinical, dermatoscopic and confocal microscopy assessment. Currently, the approach is the treatment of the field cancerization, comprising of clinically visible and subclinical AKs, for which photodynamic therapy (PDT) is a therapeutic option.
OBJECTIVE: To evaluate improvement of AKs and cancerization field in patients submitted to daylight PDT, with clinical, dermatoscopic and confocal microscopy assessment.
METHODS: Ten patients with multiple AKs on the face were selected. Daylight PDT was performed using methyl aminolevulinate and clinical, dermatoscopic and confocal microscopy photographic documentation was performed before and 60 days after the treatment.
RESULTS: Of the nine patients who completed the treatment, 8 (88.8%) showed clinical improvement and reduction in the severity of AK with one treatment. On dermatoscopy, 4 patients (44.4%) showed significant improvement, 3 patients (33.3%) showed partial improvement and 2 patients (22.2%) had no change. On confocal microscopy, 6 (66.6%) patients presented reduction in the severity of the lesion.
CONCLUSIONS: Daylight PDT proved to be effective for the treatment of AKs, with high tolerability and efficacy, besides a good safety profile.

Keywords: Dermoscopy; Keratosis, Actinic; Microscopy, Confocal; Photochemotherapy