Hair loss, or alopecia, is very common. Many conditions can cause it. Hair loss is divided into 2 categories:
- Scarring, which leads to permanent destruction of the hair follicle.
- Nonscarring, in which hair follicles remain intact.
The vast majority of hair loss is nonscarring. It includes such conditions as pattern baldness and telogen effluvium, or excessive hair shedding.
The majority of hair loss in both men and women is pattern baldness, also referred to as androgenetic alopecia. Both genetic (family) and hormonal factors play a role in pattern baldness.
Another common cause of hair loss is excessive hair shedding. Common triggers for hair shedding include a major illness, surgery, rapid weight loss, nutritional deficiency, thyroid problems, stress, and certain medications.