Acne keloidalis nuchae

Published on 18/03/2015 by admin

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Last modified 18/03/2015

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Acne keloidalis nuchae

William Perkins

Evidence Levels:  A Double-blind study  B Clinical trial ≥ 20 subjects  C Clinical trial < 20 subjects  D Series ≥ 5 subjects  E Anecdotal case reports

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Acne keloidalis nuchae (AKN) is an idiopathic chronic inflammatory process affecting the nape of the neck and the occipital scalp; it occurs predominantly in black males. Initial features consist of papules and pustules on the occiput and posterior neck, which subsequently coalesce into plaques of dense scar tissue with central scarring alopecia. Although the etiology is unknown, the histology of early cases shows evidence of acute and chronic folliculitis, with ruptured follicles, perifolliculitis, and a foreign body granulomatous response. Later cases may show similar features, but additionally there may be hypertrophic scar formation. Close shaving of the hair has been postulated as a cause for AKN, but even during the 1960s and 1970s, with the fashion for longer hair, AKN was still seen. Physical trauma due to collars rubbing and picking by patients have all been suggested as precipitants, but none of these has been investigated in any systematic way. Whether folliculitis leading to ruptured follicles and the subsequent foreign body reaction, or the development of ingrowing hairs is the primary event, the term ‘acne keloidalis’ is a misnomer. Keloids at other sites or a family history of keloids are not features of AKN, and excision of the area does not result in keloid formation. Pseudofolliculitis barbae was associated with AKN in five of six cases in one series, but clinical or histologic evidence of superficial hair penetration is lacking. Lesions resembling AKN have been reported in those receiving long-term cyclosporine, and sarcoid papules may occasionally mimic the condition.

Management strategy

A clear diagnosis is a prerequisite for the management of AKN. The presence of inflammatory papules, pustules, and hypertrophic scar formation on the occipital scalp and posterior neck in a black male is pathognomonic, but cases have been described in Caucasians, and occasionally in females. Biopsy of the area is not usually required, but concerns about keloidal scarring should not inhibit obtaining histologic confirmation. Folliculitis secondary to bacterial infections, particularly staphylococcal, needs to be excluded. In staphylococcal folliculitis the pustules and papules tend to be more widely distributed across the scalp, especially over the crown. Culture will yield heavy growths of staphylococci, and the condition usually responds well to treatment with oral antibiotics, but may recur and require long-term treatment.

In view of the suggested associations with close-cropped hair and picking, it may be worthwhile enquiring about these factors. If present, these practices should be avoided.

Treatment depends on the stage of presentation. Unfortunately, the evidence base for many of the management recommendations is weak. Many patients will prefer no treatment or conservative treatment in the early stages of the disease. This is demonstrated by the fact that only 30% of patients identified in one survey had tried any treatment at all. Early disease with papules and pustules scattered across the posterior neck and occipital scalp may well be best managed by topical antiseptics, antibiotics, or potent topical corticosteroids.

With the development of hypertrophic scar formation, topical or intralesional corticosteroids may well be of benefit. Once scarring, alopecia, hypertrophic scars, and symptoms related to itch, pain, and discharging sinuses are present, treatment directed at the removal of the follicles from the affected area in their entirety is recommended.

Excisional surgery