Hair loss is the thinning of hair on the scalp. The medical term for hair loss is alopecia. Alopecia can be temporary or permanent. The most common form of hair loss occurs gradually and is referred to as “androgenetic alopecia,” meaning that a combination of hormones (androgens are male hormones) and heredity (genetics) is needed to develop the condition. Other types of hair loss include alopecia areata (patches of baldness that usually grow back), telogen effluvium (rapid shedding after childbirth, fever, or sudden weight loss); and traction alopecia (thinning from tight braids or ponytails).
Hair loss normally occurs gradually with age in both men and women, but is typically more pronounced in men.
- Hair of the dog
An alcoholic chaser reputed to relieve a hangover, usually needed the morning after imbibing too much alcohol. There is no scientific evidence as to the efficacy of this time-honored treatment for a hangover. The saying originated in the belief that a cure for hydrophobia (rabies) or any disease contracted from a dog bite consisted of […]
- Hair, exclamation point
See Exclamation point hair.
- Hair, lanugal
The downy hair on the body of the fetus and newborn baby. The lanugal hair (or lanugo) is the first hair to be produced by the fetal hair follicles. It is very fine, soft and usually is unpigmented. The lanugal hair is prenatal hair. It appears at about 5 months of gestation and begins to […]
- Hair-on-end skull
Thin fine linear extensions radiating out from the skull that look on an X-ray like hair standing “on-end” from the skull, an appearance associated with hemolytic anemias such as sickle cell disease and thalassemia. The “hair” represents the accentuated trabeculae extending between the inner and outer skull tables through the diploe in the expanded bone […]
A wad of swallowed hair. Hairballs sometimes cause blockage of the digestive system, especially at the exit of the stomach. Also called ‘trichobezoar.