Acne Keloidalis Nuchae (AKN) is a chronic inflammatory condition affecting hair follicles on the posterior scalp and nape of the neck. This disorder involves a progressive cycle of inflammation, resulting in the formation of firm, raised, keloid-like scars and fibrotic plaques. Managing AKN is challenging, often requiring a staged, multi-faceted approach to halt disease progression and minimize visible lesions.
What is Acne Keloidalis Nuchae?
Acne Keloidalis Nuchae presents clinically as small, dome-shaped, inflammatory papules and pustules that develop on the occipital scalp and neck. Over time, these individual bumps coalesce, leading to the formation of hard, keloid-like scarring plaques that can be painful, itchy, and cosmetically noticeable. The scarring can cause permanent hair loss in the affected area, known as cicatricial alopecia.
The condition is considered a type of chronic folliculitis, which is inflammation of the hair follicle, rather than a form of common acne. While the exact cause remains uncertain, the primary mechanism involves chronic irritation and trauma to the hair follicles, which triggers an acute inflammatory response. Risk factors include frequent close shaving or trimming of the hair at the nape, wearing tight-collared shirts, or using restrictive headgear. This constant friction causes the hair shaft to break and re-enter the skin, acting as a foreign body that drives the inflammation and subsequent scarring.
AKN is most frequently observed in young adult men, particularly those of African or Hispanic descent, and is associated with naturally thick and curly hair.
Initial Management and Prevention Strategies
Management of early or mild AKN involves patient-driven preventative measures and the use of topical medications to control inflammation and infection. The primary step is eliminating the chronic mechanical trauma that initiates the inflammatory cycle. Patients should stop using trimmers or razors for close shaving at the back of the neck and instead use scissors or clippers set to a longer guard.
Changing lifestyle habits, such as avoiding high-collared shirts, tight neckwear, or restrictive athletic headgear, significantly reduces friction and irritation. Topical antimicrobial agents like benzoyl peroxide or chlorhexidine washes can be used to prevent secondary bacterial infection and reduce surface inflammation.
For mild papular lesions, a dermatologist may prescribe potent topical corticosteroids, sometimes combined with a topical retinoid. Retinoids, such as tretinoin, act as keratolytic agents to help soften coarse hairs and reduce the buildup of keratin that contributes to follicular occlusion. This combination suppresses acute inflammation and prevents the papules from progressing into larger, fibrotic plaques.
Clinical Interventions for Persistent AKN
When early topical management is insufficient, clinical interventions become necessary to reduce the size and firmness of established lesions.
Intralesional corticosteroid injections are a standard treatment for firm, raised papules and early fibrotic plaques. A corticosteroid, such as triamcinolone acetonide, is injected directly into the lesion to suppress inflammatory cells and break down excess collagen. Injections are typically administered every four to six weeks and can significantly reduce the lesion height and inflammation, though topical anesthetic may be required due to discomfort.
For lesions that show signs of infection or extensive folliculitis, systemic antibiotics, such as oral minocycline or doxycycline, may be prescribed. These medications are selected for their anti-inflammatory properties in addition to their ability to treat bacterial overgrowth.
Laser therapy is another highly effective clinical tool, particularly the 1064 nm Nd:YAG and 810 nm diode lasers. These long-wavelength lasers target the hair follicle and surrounding inflammation, offering the dual benefit of hair removal and reduced inflammatory response. By destroying the hair follicle, the source of the foreign body reaction is eliminated, which helps prevent new lesions from forming and reduces the overall progression of the condition. Multiple sessions are typically required for significant reduction.
Surgical Procedures for Advanced Cases
Surgical excision is reserved for the most advanced stage of AKN, often referred to as “tumor-stage,” where large, bulky, fibrotic plaques have formed that are unresponsive to medical and laser therapies. These masses can be disfiguring and may be associated with chronic drainage and odor. The primary goal of surgery is the complete physical removal of the diseased tissue to alleviate symptoms and improve appearance.
Elliptical excision is a common technique where the entire lesion is cut out and the remaining skin edges are stitched together to close the wound. For larger lesions, the wound may be left open to heal by secondary intention, allowing the area to granulate and epithelialize naturally, which can result in a less noticeable scar. Another technique, known as the “bat excision,” removes a wide area of tissue and allows the subsequent scar to mimic a new posterior hairline.
A significant risk with surgical removal of fibrotic tissue is the potential for recurrence or the formation of new hypertrophic scars. Therefore, surgery is followed by rigorous post-operative management to mitigate this risk. This management often involves continued use of intralesional corticosteroid injections or other non-surgical treatments to suppress residual inflammation and ensure a smooth healing process.