Leuconychia (white nails) is seen in hypoalbuminaemia. A striate congenital leuconychia exists.
Yellow-nail syndrome is a rare disorder of lymphatic drainage. It presents with thickened, slow-growing, yellow nails with associated pleural effusions, bronchiectasis and lymphoedema of the legs.
Melanonychia (longitudinal brown streaks) are seen as a normal variant in black-skinned patients. In a white patient it may reflect an underlying subungual melanoma, especially if the pigmentation progresses proximally onto the nail fold ('Hutchinson's sign').