Acne keloidalis nuchae (AKN) is a chronic inflammatory condition commonly affecting the occipital scalp and posterior neck. It causes discrete or extensive fibrosing papules that may coalesce to form pronounced tumorlike masses1,2 with scarring alopecia (Figure, A–C).3 Pustules, hair tufts, secondary bacterial infections, abscesses, and sinus tracts also may occur.1 The pathogenesis of AKN has been characterized as varying stages of follicular inflammation at the infundibular and isthmus levels followed by fibrotic occlusion of the follicular lumen.4 Pruritus, pain, bleeding, oozing, and a feeling of scalp tightness may occur.1,5
Umar et al6 performed a retrospective review of 108 men with AKN—58% of African descent, 37% Hispanic, 3% Asian, and 2% Middle Eastern—and proposed a 3-tier classification system for AKN. Tier 1 focused on the distribution and sagittal spread of AKN lesions between the clinical demarcation lines of the occipital notch and posterior hairline. Tier 2 focused on the type of lesions present—discrete papules or nodules, coalescing/abutting lesions, plaques (raised, atrophic, or indurated), or dome-shaped tumoral masses. Tier 3 focused on the presence or absence of co-existing dissecting cellulitis or folliculitis decalvans.6
Epidemiology
Acne keloidalis nuchae primarily manifests in adolescent and adult men of African or Afro-Caribbean descent.7 Among African American men, the prevalence of AKN ranges from 0.5% to 13.6%.8 Similar ranges have been reported among Nigerian, South African, and West African men.1 Acne keloidalis nuchae also affects Asian and Hispanic men but rarely is seen in non-Hispanic White men or in women of any ethnicity.9,10 The male to female ratio is 20:1.1,11 Hair texture, hairstyling practices such as closely shaved or faded haircuts, and genetics likely contribute to development of AKN. Sports and occupations that require the use of headgear or a tight collar may increase the risk for AKN.12
Key clinical features in people with darker skin tones
- The lesions of AKN range in color from pink to dark brown or black. Postinflammatory hyperpigmentation or hyperchromia may be present around AKN lesions.
- Chronicity of AKN may lead to extended use of high-potency topical or intralesional corticosteroids, which causes transient or long-lasting hypopigmentation, especially in those with darker skin tones.
Worth noting
- Acne keloidalis nuchae can be disfiguring, which negatively impacts quality of life and self-esteem.12
- Some occupations (eg, military, police) have hair policies that may not be favorable to those with or at risk for AKN.
- Patients with AKN are 2 to 3 times more likely to present with metabolic syndrome, hypertension, type 2 diabetes mellitus, or obesity.13