Fifty shades of yellow: a review of the xanthodermatoses.

The xanthodermatoses consist of a heterogeneous group of cutaneous disorders characterized by the macroscopic yellow hue seen on examination. This hue is attributable to the chemical structure of the accumulating substances within the skin or surrounding tissues. The most common culprits are lipids (cholesterol and triglycerides), elastin, and bilirubin. Exogenous sources of yellow pigment include yellow dyes (including hennas) and metal salts. This article will focus on recognition of these entities, classified in terms of morphology and the site of initial eruption, in order to support the recognition and diagnosis of these widely variable conditions.