carotenosis

Carotenosis is a benign and reversible medical condition where an excess of dietary carotenoids results in orange discoloration of the outermost skin layer. The discoloration is most easily observed in light-skinned people and may be mistaken for jaundice. Carotenoids are lipid-soluble compounds that include alpha- and beta-carotene, beta-cryptoxanthin, lycopene, lutein, and zeaxanthin. The primary serum carotenoids are beta-carotene, lycopene, and lutein. Serum levels of carotenoids vary between region, ethnicity, and sex in the healthy population. All are absorbed by passive diffusion from the gastrointestinal tract and are then partially metabolized in the intestinal mucosa and liver to vitamin A. From there they are transported in the plasma into the peripheral tissues. Carotenoids are eliminated via sweat, sebum, urine, and gastrointestinal secretions. Carotenoids contribute to normal-appearing human skin color, and are a significant component of physiologic ultraviolet photoprotection.

Carotenemia most commonly occurs in vegetarians and young children with light skin. Carotenemia is more easily appreciated in light-complexioned people, and it may present chiefly as an orange discolouration of the palms and the soles in more darkly pigmented persons. Carotenemia does not cause selective orange discoloration of the conjunctival membranes over the sclerae (whites of the eyes), and thus is usually easy to distinguish from the yellowing of the skin and conjunctiva caused by bile pigments in states of jaundice.