Acne keloidalis nuchae (AKN)
Also known as
Folliculitis keloidalis, folliculitis keloidalis nuchae, dermatitis papillaris capillitii, acne keloidalis, nuchal keloid acne, lichen keloidalis nuchae
What is Acne keloidalis nuchae?
Acne keloidalis nuchae (AKN) is a chronic inflammatory condition that affects hair follicles on the back of the neck. AKN is most commonly seen in men of African-Caribbean background but it is also seen in those of Hispanic, Asian, Middle Eastern and Mediterranean backgrounds. In rare cases, it may also be seen in Caucasians. Whilst this condition mostly affects men, women may be affected in some cases (the ratio of affected men to women is 20:1)..
The term AKN is misleading because the condition does not form true keloid scars and is not associated with acne.
What causes AKN?
The cause of AKN is poorly understood and widely debated. Possible precipitating factors include frequent short haircuts, close-shaving, chronic trauma (e.g. rubbing of shirt collar on the neck), curly hair, ingrown hairs and inflammation.
What does it look like?
In the early stages of the condition, small firm bumps, pimples and crusts form around the hair follicles on the back of the scalp (occipital scalp). As the condition progresses, the bumps enlarge and join together and may eventually form scar-like areas extending from the back of the neck up to the top of the scalp. In severe cases irreversible scarring hair loss (alopecia) may occur. Tufted (“doll-like”) hair where multiple hairs may be seen exiting from one hair follicle opening is also a feature. AKN can cause significant pain and/or itching and be distressing if it is severe. In advanced cases, abscesses with draining pus may appear.
What other problems can occur with AKN?
AKN may occur in combination with four other conditions. This group of conditions is known collectively as the “follicular occlusion tetrad” and includes hidradenitis suppurativa, dissecting cellulitis of the scalp, pilonidal sinus and acne conglobata.
How is it diagnosed?
In some cases a scalp biopsy may be required to diagnose AKN and distinguish it from other forms of scarring hair loss that look similar.
How is AKN treated?
AKN may be progressive, destructive and disfiguring. Early diagnosis and treatment is essential. Treatment is aimed at preventing scarring and permanent hair loss.
Factors that exacerbate the condition such as frequent or short haircuts, close-shaving and tight collars should be avoided.
Mild cases of AKN may be treated with topical steroids, antibiotics and retinoid creams or shampoos. In some cases stronger medicines are used to reduce the inflammation.
Moderate cases may be treated with steroid injections into the scar-like areas (intralesional corticosteroids).
Severe cases may be treated with oral antibiotics, oral retinoids or oral anti-inflammatory medications. Physical therapies such as cryotherapy, ablative laser treatment and laser hair removal may also be considered.
Surgical treatment or radiotherapy of the scarred area may be used for cases that are advanced or treatment resistant.
This information has been written by Dr Michelle Rodrigues