Carotenosis is a benign and reversible medical condition where an excess of dietary carotenoids results in orange discoloration of the Stratum corneum. The discoloration is most easily observed in light-skinned people and may be mistaken for jaundice. 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 Vegetarianism 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. eMedicine – Carotenemia : Article by Robert A Schwartz Carotenemia does not cause selective orange discoloration of the membranes over the (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.
Carotenoderma is deliberately caused by beta-carotenoid treatment of certain photo-sensitive dermatitis diseases such as erythropoietic protoporphyria, where beta carotene is prescribed in quantities which discolor the skin. These high doses of beta carotene have been found to be harmless in studies, though cosmetically displeasing to some. In a recent meta analysis of these treatments, however, the effectiveness of the treatment has been called into question.
Carotenoderma can be divided into two major types, primary and secondary. Primary carotenoderma is from increased oral ingestion of carotenoids, whereas secondary carotenoderma is caused from underlying disease states that increase serum carotenoids with normal oral intake of these compounds. Primary and secondary carotenoderma can coexist in the same patient.
Foods associated with high levels of carotenoids include:
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It is of note that kidney dysfunction in general is associated with hypercarotenemia as a result of decreased excretion of carotenoids. Liver dysfunction, regardless of origin, causes hypercarotenemia as a result of the impaired conversion of carotenoids to retinol. This is of particular interest because jaundice and carotenoderma can coexist in the same patient. Anorexia nervosa causes carotenoderma mainly through diets that are rich in carotenoids and the associated hypothyroidism. It tends to be more common in the restricting subtype of this disease, and is associated with numerous other dermatologic manifestations, such as brittle hair and nails, lanugo-like body hair, and xerosis. Although Alzheimer's disease has been associated with carotenoderma in some reports, most studies on serum carotenoids in these patients show that their levels of carotenoids and retinol are depressed, and may be associated with the development of dementia. A true association between Alzheimer's disease and carotenoderma is unclear at this time. There have been case reports in the literature of increased serum carotenoids and carotenoderma that is unresponsive to dietary measures, with a genetic defect in carotenoid metabolic enzymes proposed. Canthaxanthin and astaxanthin are naturally occurring carotenoids that are used in the British and US food industry to add color to foods such as sausage and fish. Canthaxanthin has been used in over-the-counter "tanning pills" in the United States and Europe, but is not currently Food and Drug Administration (FDA)-approved for this purpose in the United States because of its adverse effects. These include hepatitis, urticaria, aplastic anemia, and a retinopathy characterized by yellow deposits and subsequent visual field defects.
Infants and small children are especially prone to carotenoderma because of the cooked, mashed, and pureed vegetables that they eat. Processing and homogenizing causes carotene to become more available for absorption. A small 2.5 ounce jar of baby food sweet potatoes or carrots contains about 400–500% of an infant's recommended daily value of carotene. In addition to that source of carotene, infants are usually prescribed a liquid vitamin supplement, such as Tri-Vi-Sol, which contains vitamin A.
Carotenemia
(clinical vignette)
Excessive consumption of lycopene, a plant pigment similar to carotene and present in , can cause a deep orange discoloration of the skin. Like carotenodermia, lycopenemia is harmless.
Excessive consumption of elemental silver, silver dust or silver compounds can cause the skin to be colored blue or bluish-grey. This condition is called argyria. A similar skin color can result from prolonged exposure to gold, typically as a little-used medical treatment. The gold-induced greyish skin color is called chrysiasis. Argyria and chrysiasis, however, are irreversible, unlike carotenosis.
As to underlying disorders in secondary carotinemia and carotenoderma, treatment depends wholly on the cause.
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