A mottle is a pattern of irregular marks, spots, streaks, blotches or patches of different shades or colours. The term commonly describes the surface of plants or the skin of animals. In plants, mottling usually consists of yellowish spots on plants, and is usually a sign of disease or malnutrition. Many plant viruses cause mottling, including Tobacco vein mottling virus and Bean pod mottle virus.
"Mottling" is sometimes used to describe uneven, discolored patches on the skin of humans as a result of cutaneous ischemia (lowered blood-flow to the surfaces of the skin) or Herpes zoster infections. The medical term for mottled skin is dyschromia. Although not always the case, mottling can occur in a dying patient and commonly indicates that the end of life is near. Mottling usually occurs in the extremities (lower first) and progresses up as cardiac function declines and circulation throughout the body is poor. In animals, mottling may be a sign of disease, but may also be a hereditary trait, as seen with the champagne and leopard complex genes in horses.
