CASE #2: Acne keloidalis nuchae

Acne keloidalis nuchae (AKN) is a scarring eruption due to chronic inflammation of the hair follicles. AKN manifests on the nape of the neck as keloidal papules and plaques that can coalesce from juicy papules and pustules into firm plaques and nodules. The papules of AKN can be red, brown, or black with a texture that is smooth, round, or sometimes even verrucous. The papules can measure 2 mm, while the large papule-studded plaques may be as large as 2 cm. Pustules may precede the development of AKN or coexist with it. Some patients experience pain and discomfort. Because it is cosmetically disfiguring, AKN can impose a substantial psychosocial burden on patients. The condition is also known as folliculitis nuchae, folliculitis keloidis nuchae, folliculitis nuchae scleroticans, or dermatitis papillaris capillitii.

AKN was first described in 1869 by Kaposi, an Austrian dermatologist, who termed it dermatitis papillaris capillitii. Ferdinand von Hebra, author of one of the all-time most influential books on dermatology, the Atlas der Hautkrankheiten (containing some phenomenal illustrations), described AKN about the same time as Kaposi, but he dubbed it sycosis framboesiformis. In 1872, Pierre-Antoine-Ernest Bazin, a French dermatologist, named the condition acne keloidalis.


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AKN occurs sporadically. It is not linked to the follicular occlusion tetrad. For the most part, AKN and pseudofolliculitis barbae occur independently of each other. AKN most commonly affects young adult males of African origin. One case report notes two Nigerian women who developed AKN on the neck.1 AKN also occurs in Hispanics, less commonly in Asians, and rarely in whites. It has not been reported in elderly patients. Neither a family history of AKN nor a positive personal or family history of keloid formation predisposes an individual to AKN.

AKN seems to have a number of proximate causes. The primary cause is thought to be shaving of the rear scalp with a straight razor. Increased frequency of shaving that involves direct application of a blade to the skin can also be associated with acne keloidalis in that area. One case of AKN in a white patient was linked to shaving an area of skin that had been severely burned.2 Other suggested causal factors are constant irritation from shirt collars or chronic low-grade bacterial infections. An increased incidence of AKN has been reported in football players and attributed to their helmets.

Use of certain medications has been linked to the development of AKN. Cyclosporine has been associated with AKN in several case reports. AKN-like lesions on the scalp have developed following use of anti-epileptic drugs.

The differential diagnosis of AKN includes tufted folliculitis of the scalp and folliculitis decalvans, but these are more reminiscent of scarring alopecia than papular keloidal processes. Acne keloidalis can be a presentation for tinea capitis. Regular keloids, folliculitis, and nevus sebaceous of Jadassohn could theoretically mimic AKN.

The classification and etiology of AKN has engendered controversy. Some authorities have argued that AKN is a form of primary scarring alopecia, while several noted clinicians have suggested that AKN is lichen simplex chronicus with fibrotic keloidal scarring. Still others have proposed that the primary basis of AKN is infectious or autoimmune. In four cases of AKN, researchers saw histologically varying stages of transepithelial elimination, suggesting that AKN might represent a transepithelial elimination disorder akin to perforating folliculitis.

Histologic examination demonstrates that AKN is not an acneiform process. In AKN, inflammation begins at the deep infundibular and isthmic levels of the hair follicle and is accompanied by absence of sebaceous glands. Acute folliculitis and perifolliculitis, with destruction of the follicular wall and the release of hair, may be noted. Central follicles can manifest predominantly acute neutrophilic or chronic lymphocytic inflammation at the upper isthmian levels and granulomatous inflammation at the deeper isthmian levels. Trapping hair fragments in the inferior portion of the follicle, with granulomatous inflammation and scarring, can result in AKN.

A variety of medical and surgical treatment modalities exist for AKN. First-line treatment is an ultrapotent topical corticosteroid. The gel form is probably most effective, as it will stick to the area and can be rubbed in immediately. Clinicians who prescribed topical clobetasol propionate foam for 8-12 weeks found that it was effective in improving AKN and had good patient acceptance.3 A topical retinoid, such as tazarotene (Tazorac), can be added and mixed with the topical steroid. Intralesional triamcinolone (Kenalog) can be injected into the area at a concentration of 3-10 mg/mL. Successful treatment of AKN with isotretinoin (e.g., Accutane) has been observed. One report noted that keratosis follicularis spinulosa decalvans in association with AKN responded to oral isotretinoin 20 mg (0.25 mg/kg) daily for 12 months.4 Silicon gel-sheet coverage has been reported effective, but I have not found this to be true in my practice. Topical clindamycin can be used to control pustules.

Surgery is usually reserved for more difficult-to-treat AKN. Excision and second-intention healing technique is sometimes helpful. AKN can be shaved down with a dermatome; when this is the approach used, I would suggest, cost considerations aside, that imiquimod (Aldara) be applied to the raw eroded skin. Both the diode and carbon dioxide lasers have been noted in case reports to be beneficial.5,6 One patient with AKN was treated with chronic tissue expansion, total resection, reconstruction of the injured area by advancing the flap of the expanded scalp, and local radiotherapy to the resultant scar. The outcome was total clearance that persisted for at least two years after treatment was stopped.7 Thus extensive sur-gery and superficial x-ray therapy can be used in recurrent and difficult-to-treat cases.

Intermittent generic clobetasol propionate gel relieved this patient’s itching. Note that continuous long-term use of clobetasol should be avoided.

Dr. Scheinfeld is assistant clinical professor of dermatology at Columbia University in New York City, where he has a private practice.


References

1. Ogunbiyi A, George A. Acne keloidalis in females: case report and review of literature. J Natl Med Assoc. 2005;97:736-738.
2. Körlof B, Doebler WD, Lagerholm B. Acne keloidalis of the burned male face. Case report. Scand J Plast Reconstr Surg. 1979;13:358-360.
3. Callender VD, Young CM, Haverstock CL, et al. An open label study of clobetasol propionate 0.05% and betamethasone valerate 0.12% foams in the treatment of mild to moderate acne keloidalis. Cutis. 2005;75:317-321.
4. Goh MS, Magee J, Chong AH. Keratosis follicularis spinulosa decalvans and acne keloidalis nuchae. Australas J Dermatol. 2005;46:257-260.
5. Kantor GR, Ratz JL, Wheeland RG. Treatment of acne keloidalis nuchae with carbon dioxide laser. J Am Acad Dermatol. 1986;14(2 Pt 1):263-267.
6. Shah GK. Efficacy of diode laser for treating acne keloidalis nuchae. Indian J Dermatol Venereol Leprol. 2005;71:31-34. Accessed March 18, 2009.
7. Pestalardo CM, Cordero A Jr, Ansorena JM, et al. Acne keloidalis nuchae. Tissue expansion treatment. Dermatol Surg. 1995;21:723-724.