Pigmentary Disorders in Black Skin from Pathophysiology to Treatment

Abstract

Pigmentary disorders are frequent and more visible in patients with darker phototypes (Fitzpatrick’s IV–VI). They also have an important psychological impact and are the cause of inappropriate cosmetic practices. Pigmentary disorders comprise a wide range of pathologies, and the pathophysiological mechanisms have evolved considerably in recent years. Pigment disorders vary in their clinical presentation from achromia to hyperpigmentation to hypopigmentation. Inflammatory dermatoses, such as acne, are often complicated by postinflammatory hyperpigmentation; psoriasis and lichen planus are accompanied by dyschromia. Some skin diseases, such as mycosis fungoides, have atypical presentations in the form of hypopigmented plaques. All these dyschromias have an important impact on the quality of life and are responsible for practices such as voluntary cosmetic depigmentation with products like dermocorticoids, hydroquinone and mercury salts, and various depigmenting products. This practice is at the origin of pigmentary disorders, such as exogenous ochronosis, lichen-like and lupus-like dermatoses, and periorbital hyperpigmentation. Therapeutic management is difficult and relies on chemical (peeling), physical (laser), and medicinal means (tranexamic acid); hence, the interest is in prevention through early diagnosis and the avoidance of favorable factors.