What causes acne keloidalis nuchae?

The condition begins when hairs and surrounding skin become irritated. A very close haircut or razor shave can make short, curved hairs re-enter the skin. Collars, helmets, sports equipment, and scratching may add rubbing. The resulting inflammation can form firm itchy bumps, usually along the back of the scalp and upper neck. Ongoing inflammation may lead to raised scars or patches where hair no longer grows.

It is not caused by poor hygiene, and it is not the same as ordinary facial acne. Razor bumps, also called pseudofolliculitis barbae, involve a similar ingrown-hair mechanism.

Avoid close shaving at the back of the neck while the skin is active. Choose a guarded trimmer, leave a little hair length, and clean equipment before use. Reduce rubbing from tight collars or headwear, and do not pick, squeeze, or scratch the bumps. A dermatologist can assess whether an anti-inflammatory, antimicrobial, or hair-reducing treatment fits your skin and the stage of scarring.

Arrange a dermatology assessment if bumps keep returning, become painful, drain, spread, or leave firm scars. Seek prompt care for rapidly increasing redness, warmth, swelling, pus, fever, or severe tenderness, because these may signal infection. Early treatment can calm follicle inflammation before scarring becomes more established.

Ask whether the bumps are acne keloidalis nuchae or another follicle condition, which grooming changes are safest, and whether existing scars need separate treatment. You can also ask how to recognise infection and when it is safe to resume trimming.