A dual organism whose body is made of a fungus, usually an ascomycete, and a blue-green alga or cyanobacterium.
A type of skin disease with thick skin and small lesions.
Any of several skin disorders characterized by thickened, hardened lesions grouped closely together.
Any of several types of skin disease in which small round hard lesions occur close together. For example, lichen planus is an inflammatory condition in which wide flat mauve pimples are found mainly on the forearms, neck, and between the thighs.
Lichen, or lichenification, is term used to describe a thickening of chronically inflamed skin, giving rise to a tree-bark-like appearance.
This term is used to describe a broad category of skin disorders characterized by raised papules with pronounced skin markings. The two most frequently encountered conditions within this category are lichen planus and lichen simplex.