What is the medical term for excessive hair loss?

The medical term for excessive hair loss is alopecia. It is a broad term describing loss of hair from part of the head or body, rather than the name of one single disease or cause.

Alopecia includes several different conditions. Androgenetic alopecia causes common male- and female-pattern hair loss through genetic and hormonal influences. Alopecia areata is an autoimmune condition that can produce sharply defined patches, while telogen effluvium can cause increased shedding after physical or psychological stress, illness, or pregnancy.

The word comes from the Classical Greek alōpēx, meaning “fox,” probably referring to the seasonal shedding of a fox’s coat or to hair loss associated with mange in ancient Greece. This is why “alopecia” is used clinically even when the underlying cause differs.

Alopecia should not be confused with hirsutism or hypertrichosis, which involve excessive hair growth. The amount and pattern of hair loss help clinicians investigate possible causes, which can include genetics, autoimmune disease, medications, nutritional deficiencies, or scalp disorders.