There are three main mechanisms involved in hypercarotenemia: excessive dietary intake of carotenoids, increased serum lipids, and decreased metabolism of carotenoids. The most common reported cause of hypercarotenemia (and thus carotenoderma) is increased intake, either through increased dietary foods or nutritional supplements. This change takes approximately 4 to 7 weeks to be recognized clinically. Numerous ingested substances are rich in carotenoids. Increased serum lipids also cause hypercarotenemia because there are increased circulating lipoproteins that contain bound carotenoids. Finally, in certain disease states, the metabolism and conversion of carotenoids to retinol is slowed, which can lead to decreased clearance and increased plasma levels. Elevated serum beta-carotene does not necessarily result in carotenosis, but the latter is likely to show up when intake is more than 20 mg/day. Average adult intake in the U.S. around 2.3 mg/day. One medium-sized carrot has about 4.0 mg.

Carotenoderma can be divided into two major types, primary and secondary. Primary carotenoderma is that developing 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:

Disease states associated with carotenoderma include hypothyroidism, diabetes mellitus, anorexia nervosa, nephrotic syndrome, and liver disease. In hypothyroidism and diabetes mellitus, the underlying mechanism of hypercarotenemia is thought to be both impaired conversion of beta-carotene into retinol and the associated increased serum lipids. Diabetes mellitus has also been associated with carotenoderma through disease-specific diets that are rich in vegetables. In the nephrotic syndrome, the hypercarotenemia is related to the associated increased serum lipids, similar to the above entities.

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.