Cryopeeling versus trichloroacetic acid peeling in the treatment of solar lentigines: Effect on epidermal Langerhans cells.

Trichloroacetic acid (TCA) peeling may be effective in solar lentigines, but with concerns regarding potential tumorigenesis. Cryopeeling would be better with improving the whole sun-damaged skin. We aimed to compare the efficacy and safety of cryopeeling and TCA 35% peeling for treatment of solar lentigines and assess their influence on the number of epidermal Langerhans cells (LC). Twenty-five patients were treated with TCA 35% and cryopeeling on the right and left hands, respectively. Two sessions were done 3 weeks apart. Evaluations were scheduled at weeks 0, 3, and 6. Skin biopsies, taken before and after treatment, were evaluated histologically and immunohistochemically for the number of CD1a + epidermal LCs. Lentigines decreased after cryopeeling from the first session (p < .001), but after the second session with TCA peeling (p = .004). Cryopeeling produced significant lightening, compared with TCA (p = .015). Blistering, hyper/hypopigmentation were reported with cryopeeling, whereas only hyperpigmentation was noted after TCA peeling. The LCs remained at about the pretreatment number after cryopeeling (p = .058), though they decreased after TCA (p = .002). Cryopeeling provided faster and superior improvement of lentigines compared with TCA peeling. Furthermore, TCA seems to suppress LCs raising the concern for carcinogenic potential.