There are four ways that head trauma can cause hair loss.
The first way results in temporary hair loss, when the hit to the head actually takes hair with it, ripping it from the follicles.
The follicles are not damaged, and the hair will grow back.
Another Way Getting Hit in the Head Can Cause Hair Loss
“Head trauma can cause hair loss where scar tissue has formed,” says Dr. Janet Prystowsky, board certified dermatologist in New York, NY, with 30+ years’ experience. “In this case, hair will not regrow in that area.”
The third way is when the trauma to the head literally scoops out a large enough chunk of scalp that the hair follicles, not just uprooted strands of hair, are taken with it.
You now have no hair follicles in the injured area.
However, don’t rule out the possibility that transplanted follicles from donor sites elsewhere on your head can give you hair in that bald area.
Shock Causes Hair Loss; Head Trauma Is Shock
If the hit to your head is severe enough, it can trip up the chemical balance in the body.
This creates a ripple effect that leads to hair loss, even though the point of impact to your head did not rip out any hair or pieces of scalp with follicles.
Good news: Hair loss from getting banged in the head, without actual damage to the follicles or uprooting of the strands, is temporary.
This is because as the body recovers from the shock of the injury, the growth cycle of the hair will become restored.
But the regrowth won’t occur overnight. It may take three to six months.
Hair grows in cycles or phases, and these can get knocked out of whack by enough physical trauma — even trauma that does not involve the head.
Hair loss is triggered while growth is suppressed while the hormones are trying to figure out what’s happened.