Axillary hyperpigmentation is a most frequent and common cause of cosmetic consultations in dark-skinned women especially from tropical areas. It is typically treated with bleaching agents as it is considered as a variant of inflammatory hyperpigmentation. The main objective of this study was to evaluate the efficacy of niacinamide 4% and desonide 0.05% emulsions when compared with placebo in the axillary hyperpigmentation treatment.

Twenty-four women who were aged between 19-27 years with hyperpigmented axillae (phototype III-V) were randomly allocated to have the study treatments in the axillary region. Improvement was evaluated at baseline clinically and by colorimetry later 9 weeks. Quantitative assessment that included melanin, collagen type IV content, inflammatory infiltrates, NKI/Beteb, CD1a, CD68, was done by histochemistry and immunohistochemistry.

The results of the study showed that both niacinamide and desonide made significant colorimetric improvement as compared with placebo. A response of good to excellent was seen in 24% of cases for niacinamide. A notice able disruption of the basal membrane in axillary hyperpigmentation and an inflammatory infiltrate improved after the treatment. Decrease in pigmentation was observed in the niacinamide-treated axillae and correlated with recovery of disruption at the basal membrane.

The study concluded that niacinamide exhibited depigmenting properties in women with axillary hyperpigmentation. The positive findings could be due to the antimelanogenic and anti-inflammatory properties of niacinamide and desonide, respectively.

Source: Castanedo-Cazares JP, Lárraga-Piñones G, Ehnis-Pérez A, et al. Topical niacinamide 4% and desonide 0.05% for treatment of axillary hyperpigmentation: a randomized, double-blind, placebo-controlled study. Clin Cosmet Investig Dermatol. 2013;6:29-36. doi:10.2147/CCID.S39246