Alopecia is the medical term for hair loss. The normal amount of hair loss is around 100-250 hairs daily.
Each hair follicle has its own life cycle which is composed of three phases:
Anagen - the actively growing phase, which most hair follicles are in and generally lasts between 2-8 years
Catagen - the transitional phase lasts for 2-3 weeks during this time the hair growth stops and the follicle shrinks, only 1% - 3% of all hairs are in the catagen phase at a given time
Telogen – the resting phase is when the follicle remains dormant for 1-4 months until the hairs are shed, this affects 10% of hair at a given time.
There are several different types of hair loss the most common being
androgenetic alopecia also known as male or female pattern hair loss. This hair loss is due to a combination of hormones (androgens) and genetic predisposition. For males this hair loss is characterized by a receding hair line and hair loss at the front and top of the head. Female pattern hair loss presents most commonly as hair loss at the mid frontal scalp and widening of the hair part.
Telogen effluvium is temporary hair loss caused by a large numbers of hairs being in the telogen phase. When the body goes through a stress the shock sends more of the hair into the resting phase which then causes hair shedding. The stressor usually occurs months prior to the hair loss. Some of the most common precipitants are illness, surgery, childbirth, accident, weight loss, certain medications, and personal stress. The hair will come back but it may take 6-9 months.
Alopecia areata is an autoimmune condition where the body attacks its own hair follicles causing sudden round patches of hair loss on the scalp or body.
Effective treatments for some types of hair loss are available. Your dermatologist will use diagnostic tests including but not limited to blood tests and scalp biopsy to determine the best course of treatment.