Hi, I am a 21-year-old female. I have always had seborrheic dermatitis, so my scalp has always been scrubbed during shampoos, with nails, until I was about 16, when I learned it was not alright to do.
Sometimes (about a few times a year) I scratch my seborrheic dermatitis if it is itchy, or run my fingertips through my hair (with a bit of pressure) to push out blackheads on the scalp. Hair rarely comes out. Today I was running my fingers through my hair (with pressure) intermittently all day, and ended up losing about 10-20 hairs (I did not comb or wash my hair for a few days, though). When I play with my boyfriend’s hair, I end up removing his blackheads too, through fingertip-rubbing, about a couple times a month. Did I cause any permanent damage to our hair follicles?
If you pick at your scalp and repeat the process in the same area, you may lose hair permanently (see Trichotillomania Learning Center). So while I don’t know if you caused permanent loss, it’s doubtful at this point. Losing 100 hairs a day is normal, and since you didn’t comb or wash your hair for a few days it’s entirely possible that those hairs were already fallen out and just trapped.
Seborrheic dermatitis is a common condition and there are many good commercial products out there that can address it with traditional shampoos like Head and Shoulders (one of my favorites).