Photodynamic therapy of actinic keratosis with topical 5-aminolevulinic acid. A pilot dose-ranging study

To examine the safety and efficacy of photodynamic therapy using topical 5-aminolevulinic acid (ALA) and red light to treat actinic keratoses (AKs).

Actinic keratoses were treated with topical ALA (concentrations of 0%, 10%, 20%, or 30%) under occlusion for 3 hours. Before photodynamic therapy, sites were examined for fluorescence. Sites were irradiated with an argon pumped dye laser (630 nm) at fluences of 10 to 150 J/cm2.

Academic medical center.

Forty patients with 6 clinically typical, previously untreated AKs per patient.

Complete resolution and decrease in lesion area of the AK relative to baseline evaluated at weeks 1, 4, 8, and 16.

Three hours after ALA administration, lesions showed moderate red fluorescence. Cutaneous phototoxic effects, localized erythema and edema, peaked at 72 hours. Patients experienced mild burning and stinging during light exposure. Eight weeks after a single treatment using 30% ALA, there was total clearing of 91% of lesions on the face and scalp and 45% of lesions, on the trunk and extremities. No significant differences were observed in clinical responses with treatment using 10%, 20%, or 30% ALA. All concentrations of ALA were more effective than treating AKs with vehicle and light.

Topical photodynamic therapy with ALA is an effective treatment of typical AKs. Complete clearing of nonhypertrophic AKs can be achieved with 10%, 20%, or 30% ALA that is easily tolerated by the patient. Lesions on the face and scalp are more effectively treated than lesions on the trunk and extremities. Hypertrophic AKs did not respond effectively.