piebald

Piebald refers to a color pattern characterized by patches of unpigmented white skin, hair, or plumage alternating with pigmented areas. The term derives from the magpie, whose plumage combines black and white patches; "bald" historically referred to white patches.

In humans, piebaldism is a rare congenital genetic condition caused primarily by variants in the KIT gene that disrupt melanocyte development. It typically presents at birth with sharply demarcated patches of depigmented skin and hair, often including a white forelock. Patches remain relatively stable over time and may be accompanied by midline hypopigmented areas or sensorineural anomalies in rare cases. Piebaldism is distinct from vitiligo and albinism and is usually inherited in an autosomal dominant pattern with variable expressivity.

In animals, piebald describes a similar appearance of white patches on a pigmented background. It is commonly applied to horses (a piebald horse is black-and-white), but occurs in many species, including dogs, cats, cattle, and poultry. The pattern results from genetic variation that affects the migration and survival of melanocytes during embryonic development. In some contexts, piebaldism is simply a normal color variant, while in others it may be superseded by breeding standards that emphasize specific patch shapes and distributions. Differences between terms such as piebald, skewbald, and pinto reflect variations in base color and patch placement across breeds and disciplines.

See also: vitiligo and albinism as related concepts.