Inflammation of scalp hair follicles, often causing itchy or sore bumps and pustules.
Scalp folliculitis can cause small inflamed spots around follicles, itch, soreness, crusting or pustules. It is not the same as androgenetic alopecia, but repeated inflammation, scratching or more severe follicular disease can worsen the appearance of hair density. Causes can include bacteria, yeast, occlusion, irritation or inflammatory conditions. Treatment depends on severity and may involve medicated shampoos, topical antimicrobials, oral antibiotics or assessment for scarring folliculitis if there is tufting, pain or permanent hair loss.
DermNet scalp folliculitis: https://dermnetnz.org/topics/scalp-folliculitis