Alopecia – hair falls out in the same area all at one time. Kind of like crop circles.
3 Stages of the Hair Follicle life cycle
– Anagen phase – active phase, cells are multiplying, hair is growing
– Catagen phase – resting phase, “cat nap”
– Telogen phase – shedding phase
Hair thickness is determined by 2 things: the density of hair follicles (how many follicles in one area) and how large a single hair follicle is (thick vs fine hair).
male patterned baldness – receding hairline from front to back, and the loss of the hair on the crown of the head.
Female patterned baldness – the overall thinning of the hair.
Hirsutism – females get male-patterned balding due to testosterone imbalance
Why does all your hair fall out after you have a baby??
Telogen effluvium – a mass exodus of hair follicles
This can also happen when the body goes through extreme shock or trauma.
There is a condition called post-partum alopecia – this is temporary, and hair grows back afterwards.
Dandruff – caused by the inflammation of the scalp. Inflammation causes skin to be dry and itchy. The topmost skin layer releases in larger amounts, thus the pieces are visible, opposed to when the skin naturally sheds, it’s microscopic so you don’t usually see the dead skin cells you lose.
Tinea capitis – ringworm on your scalp, aka cradle cap. Usually requires an antifungal to get rid of it.
Hair can actively grow for up to 6 years.
Since hair is dead cells, hair hangs onto the DNA and it can be used to identify people (missing persons) or for paternity tests (who’s your daddy)?
Dying and perming affect the proteins that give it color or keep it connected.
If someone has had prolonged exposure to toxin (carbon monoxide, heavy metals, smoking), the hair shows markers of that damage from the toxins. It can also hang on to markers from being exposed to illicit drugs. It’s like a timeline of what you’ve been exposed to.