Folliculitis decalvans https://en.wikipedia.org/wiki/Folliculitis_decalvans
Folliculitis decalvans is an inflammation of the hair follicle that causes induration of the affected scalp, accompanied by pustules, erosions, crusts, ulcers, and scaling. It leaves scarring, sores, and, due to the inflammation, hair loss. The exact cause is unknown, but the bacterium Staphylococcus aureus plays a central role.

Treatment ― OTC Drugs
All acne medications may be tried, but in most cases the symptoms are severe enough that a doctor should be consulted for oral antibiotics.
#Benzoyl peroxide [OXY-10]
#Bacitracin

Treatment
#Minocycline
#Isotretinoin
More information ― English
References Acne Keloidalis Nuchae 29083612 
NIH
Acne keloidalis nuchae is a disease characterized by persistent folliculitis at the nape of the neck that forms keloid like scars and ultimately cicatricial alopecia. The disorder is most common in young African American males.