Introduction: Photodamaged skin of the anterior thorax region is characterized by flacidity, wrinkles, hyperpigmentation, erythema, telangiectasia, and atrophy. Microneedling has been used for the transdermal drug delivery of active agents to the skin through microchannels. Objective: To clinically evaluate the rejuvenation of the skin of the anterior thorax region resulting from the use of microneedling associated with drug delivery. Methods: Double-blind randomized, placebo-controlled study conducted with 22 women who underwent three microneedling sessions followed by the topical application of a test product containing hyaluronic acid and other active principles or placebo. The evaluation was performed through photographic comparison carried out by a dermatologist oblivious to the study and the application of self-assessment questionnaires to patients. Results: Clinical evaluation showed improvement in the overall skin rejuvenation of the anterior thorax region in 100% of the patients. The statistical analysis showed a 28% improvement (p <0.05) with use of the test product as compared to the placebo. The responses to the questionnaires demonstrated an improvement of 30% in the patients treated with microneedling and the test product. Conclusions: The microneedling technique associated with the transdermal administration of drugs used for rejuvenation provides improved overall appearance of the skin of the anterior thorax region, with a high degree of tolerability and satisfaction.

Keywords: REJUVENATION; COLLAGEN; ADMINISTRATION; CUTANEOUS

INTRODUCTION: The chest is a photoexposed area that shows effects of photodamage. Microneedling is a safe option for the rejuvenation of this area, also leading to improvement in dyschromias.
OBJECTIVE: To evaluate histologic cutaneous response after three monthly sessions of microneedling for the treatment of dyschromias on the chest.
METHODS: Three monthly sessions of microneedling, with 1.5mm length needles were performed, as well as skin biopsies before and 90 days after commencement of the study. Histologic samples were evaluated with H&E and Fontana-Masson stains. Melanin content was measured based on dermal clusters.
RESULTS: Six patients between 38 and 67 years of age, phototypes II-III, Glogau scale II-IV were included. A positive correlation was observed between the time and dermal content of melanin (p=0.029): three sessions of microneedling reduced this content on D90 compared to the beginning (6.4 ± 1.7 MC on D0 versus 3.1 ± 0.4 on D90, p = 0.05). Three patients reported global skin improvement on D90.
CONCLUSIONS: The proposed mechanism of microneedling to promote lightening includes fibroblast proliferation and neocollagenesis in the upper dermis. This is the first study to evaluate the histology of the findings associated to lightening of the chest due to microneedling.

Keywords: Histology; Melanins; Needles; Thorax