Laser therapy of freckles and lentigines with quasi-continuous, frequency-doubled, ND:YAG (532NM) laser: A preliminary report

Traditional treatment for freckles and lentigines are often ineffective and associated with significant complications. Newly developed lasers produce excellent results with minimal complications. The aim of this ongoing study is to assess the efficacy and safety of quasi-continuous frequency-doubled Nd:YAG (532 nm) laser in the treatment of these lesions. Twenty adult patients (14 with freckles and 6 with lentigines) were enrolled in the study. In phase I, three test sites in each patient were irradiated with fluences of 1.45, 2.90, and 7.25 J/cm², one fluence per site. Three months after single treatment, the fluence yielding the best response was selected for subsequent treatment of remaining lesions in phase II. In phase II, variable number of treatments were administered at minimum of four weeks interval. Treatments would continue till no additional improvement occurs. Patients completing phase II were followed up monthly. In phase I maximum improvement (grade 3 and 4 response i.e. >50% in 50% of patients) was noted with 7.25 J/cm² (p<0.02), followed by 2.90 J/cm² (>50% in 5% of patients) and 1.45 J/cm² (>50% in none). In phase II, 1.5 (75%) of 20 patients manifested more than 50% improvement (p< 0.05). The patients were irradiated 2-6 times at 4-12 weeks intervals. Complications included hypopigmentation (25%), atrophy (15%) and hyperpigmentation (10%). All these were mild and resolved within 2-6 months. No recurrence was noted in 5 patients who had completed the phase II during a mean follow up period of 3.6 months. Quasi-continuous, frequency- doubled Nd:YAG (532 nm) laser safely and effectively treats freckles and lentigines.