Management of hyperpigmentation in the armpits and groin folds with a depigmenting dermo-cosmetic product

Repeated rubbing can lead to localized hyperpigmentation (armpits, groin, elbows, knees, etc.), particularly in darker phototypes. Less well-known than hyperpigmentation in senile lentigo, melasma, or post-inflammatory hyperpigmentation type, these friction melanoses nonetheless affect women's quality of life. A clinical study was therefore conducted to assess the efficacy and safety of a specific whitening depigmenting dermo-cosmetic product and adapted to these particularly sensitive parts of the body.

A randomized, controlled and comparative trial was conducted in Brazil on 72 subjects under dermatological or gynecological control depending on the group: one group of subjects with hyperpigmentation in the armpits (group 1) and the other in the groin folds (group 2), with a clinical pigmentation score > 1.0 and > 0.5, respectively. The tested product contains a patented combination of depigmenting active ingredients (Andrographis paniculata leaf extract, Glycyrrhiza glabra [licorice] root extract, azelaic acid), and a soothing Laminaria ochroleuca extract. It was applied twice a day for 56 days (D56) after cleaning the pigmented area. Depigmenting efficacy was assessed at D0, D28 and D56 on the affected areas by measuring the lightening, using: (i) a grading scale from -4.0 (intense lightening) to +4.0 (intense darkening), (ii) a chromameter to assess luminance and skin color (the higher the ITA° [Individual Typological Angle] the lighter the skin), and (iii) photographs. Underarm photographs were also used to quantify the pigmented area. Moreover, the subjects judged the subjective efficacy of the product at D56 using a questionnaire. Skin safety was assessed at D28 and D56 by a dermatologist (group 1) or a gynecologist (group 2).

The 31 subjects per group who completed the study had an average age of 36 years (18 to 53 years) for group 1 and 35 years (18 to 55 years) for group 2. For both groups, the score of hyperpigmentation decreased by -9.1% at D56, and -4.5% for group 2 from D28. Luminance increased significantly from D28 by +3.6% for group 1 and +8.3% for group 2, and at D56 +7.1% and +12.7% respectively, as well as for ITA° +33.3% and +36.6% at D28, and +52.5% and +75.0% at D56 for groups 1 and 2, respectively. The significant increase in these parameters reflects a lightening effect on these areas. At the same time, the pigmented area decreased by -45.7% at D28 and -80.7% at D56 for group 1. 80 to 90% of the subjects judged the product to be effective in preventing new brown spots, but also in reducingspots, and marks installed. No adverse effects or discomfort related to the product have been reported during the study.