The term hair loss means the reduction in the number of hairs on your scalp. It also refers to a gradual conversion of hairs from the healthy to a tiny state.
There are 2 types of hair loss: 1- Temporary. 2- Permanent.
Temporary (physiological) hair loss:
- Our scalp hairs grow for 2-6 years then shed in 3-6 months. A new hair is produced from the same hair follicle and then the cycle resumes again.
- In a given time, 90 % of our hairs are in the growth phase, the remaining hair is in the resting or shedding phase. Seeing 50-100 hairs daily stuck to our hairbrushes is normal and means that it is a physiological hair loss.
Natural growth and fall cycles of scalp hair.
Permanent hair loss:
- Progressive androgenic or genetic alopecia in men causes an irreversible miniaturization of the hair follicles. The follicles shrink and start producing thinner and shorter hair permanently.
- The growth phase of the hairs shortens, whereas the resting phase lengthens. The hairs are eventually shed permanently and baldness starts to develop.
Miniaturization of the hair follicles in male androgenic hair losses.
Normal hair cycle (temporary loss) and alopecia phases (permanent loss):
Scalp: The skin on the head from which hair grows.
Hair follicle: The smallest but also a very complex human organ which produces a single hair throughout our life.
Hair shaft: Body of the hair, it refers to a hair.
Anagen phase: A growth phase of hair, it lasts 2-6 years.
Catagen phase: Hair production stops and the hair shafts become separated from their follicles, this lasts 1-2 weeks.
Telogen phase: A resting, no-growth phase of hair, it lasts 5-6 weeks. During this phase, the hair can be easily pulled out by traction.
Early anagen phase: The responsible hair follicles begin to produce new hair from underneath the skin.
Alopecia: Permanent hair loss, may be in the form of shedding or thinning of the hairs.
Baldness: Total loss of hair in a particular area or areas of the scalp.