MedGen

A noncongenital process of hair loss, which may progress to partial or complete baldness. [from HPO]

A finding of a localized protective response resulting from injury or destruction of tissues. Inflammation serves to destroy, dilute, or wall off both the injurious agent and the injured tissue. In the acute phase, inflammation is characterized by the signs of pain, heat, redness, swelling, and loss of function. Histologically, inflammation involves a complex series of events, including dilatation of arterioles, capillaries, and venules, with increased permeability and blood flow; exudation of fluids, including plasma proteins; and leukocyte migration into the site of inflammation. [from NCI]

Loss of scalp and body hair involving microscopically inflammatory patchy areas. [from MONDO]

Androgenetic alopecia is characterized by a loss of hair from the scalp that follows a defined pattern (Hamilton, 1951). It occurs in women as well as in men. It is caused by a shortening of the anagen (growth) phase and miniaturization of the hair follicle, which results in the formation of progressively thinner, shorter hair (Bergfeld, 1995). In men, the condition is often referred to as male pattern baldness (MPB) and appears to be androgen-dependent (Hamilton, 1942). The condition is hereditary, and follows a pattern that may be consistent with an autosomal dominant trait (Osborn, 1916). Linkage evidence for an autosomal locus on 3q26 (AGA1) has been identified (Hillmer et al., 2008). See 300710 (AGA2) for a discussion of X linkage of androgenetic alopecia. A third locus has been found on chromosome 20p11 (AGA3; 612421). [from OMIM]