Acne Keloidalis Nuchae (AKN) is a chronic inflammatory skin condition that develops on the occipital scalp and the nape of the neck. It is characterized by persistent inflammation of the hair follicles, which eventually leads to the formation of firm, raised scars. The condition is often misnamed, as it is not a form of common acne, nor are the resulting scars true keloids. Understanding this unique form of scarring alopecia is important for recognizing the progression of the condition and seeking appropriate medical management.
Understanding Acne Keloidalis Nuchae
The physical manifestation of AKN begins as chronic folliculitis. These initial lesions appear as small, firm, dome-shaped papules, which are often itchy or mildly painful. Over time, this persistent follicular inflammation causes the hair shaft to rupture beneath the skin surface, triggering an intense immune response.
The body’s repair process results in the formation of dense, keloid-like scar tissue, a process known as fibrosis. These individual papules and inflammatory nodules can merge to form larger, elevated, and firm plaques. This extensive scarring leads to permanent hair loss, or cicatricial alopecia, in the affected area.
The appearance of tufted hairs, where multiple hair shafts emerge from a single follicular opening, is a common feature seen at the periphery of the established plaques. Unlike typical acne lesions, AKN does not commonly feature comedones. It progresses through distinct stages of inflammation and fibrotic change.
Underlying Causes and Primary Risk Factors
The condition is strongly associated with chronic, low-grade mechanical trauma to the nape of the neck. Repeated friction from habits like close shaving, especially when using electric clippers or razor blades that cut the hair below the skin line, is a significant initiating factor. This trauma, along with constant rubbing from stiff shirt collars, helmets, or restrictive athletic gear, can trigger the initial inflammatory response in the hair follicles.
The pathogenesis is also closely linked to the morphology of the hair shaft, particularly among individuals with tightly curled or kinky hair. When these coarse, curved hairs are cut, they are more likely to curl back and penetrate the adjacent skin, leading to an ingrown hair phenomenon that incites inflammation. This process is similar to pseudofolliculitis barbae, which affects the beard area.
Genetic predisposition plays a considerable role, as the condition predominantly affects men of African descent, with a male-to-female ratio estimated at approximately 20-to-1. It typically starts after adolescence, suggesting a possible influence from androgen hormones on hair follicle characteristics. Poor hygiene is not a cause of AKN, though secondary bacterial infections can complicate existing lesions.
Clinical Diagnosis and Severity Staging
The diagnosis of AKN is clinical, requiring a visual and tactile examination of the affected area by a dermatologist. The characteristic appearance of follicular-based papules, pustules, and firm, raised plaques on the occipital scalp and nape of the neck is often sufficient for identification. A thorough patient history, including hair-cutting routines and the use of headgear, helps confirm the diagnosis.
In some complex or non-responsive cases, a skin biopsy may be performed to rule out other similar conditions, such as dissecting cellulitis of the scalp. The biopsy helps confirm the diagnosis by showing the specific pattern of inflammation, follicular destruction, and excessive collagen deposition characteristic of AKN.
To guide treatment decisions, dermatologists typically categorize AKN based on the severity and extent of the lesions. Early stages are defined by small, discrete papules and pustules, while more advanced stages involve the coalescence of these lesions into larger, fibrotic plaques. The most severe stage involves the formation of large, tumorous masses that extend across a significant area of the scalp and neck.
Current Treatment Approaches
The goal of treatment is reducing inflammation and preventing the progression of scarring. For early, mild cases characterized by isolated papules, treatment often begins with topical medications. These include high-potency topical corticosteroids to suppress inflammation and topical antibiotics, such as clindamycin or benzoyl peroxide washes, to reduce bacterial colonization and secondary infection risk.
If papules are firm or fail to resolve with topical therapy, the next step involves intralesional corticosteroid injections. Injecting the medication directly into the lesions can soften and flatten the papules and small plaques by providing a high concentration of anti-inflammatory agent. This is often combined with a course of oral antibiotics, such as doxycycline or minocycline, which are prescribed for their anti-inflammatory properties over several weeks or months.
For cases that are more resistant to medication, laser therapy has become an effective treatment option aimed at permanent hair removal to stop the cycle of ingrown hairs and inflammation. Lasers are commonly used, effectively targeting the hair follicles to induce destruction. This permanent removal of the follicular unit halts the foreign body reaction that drives the scarring process.
Advanced cases involving large, bulky, or coalesced plaques that cause significant disfigurement or pain often require surgical excision. During this procedure, the entire mass of scarred tissue is removed, and the skin edges are brought together with a focus on achieving tension-free wound closure to minimize the risk of recurrence. Lifestyle adjustments, such as avoiding close shaves, wearing loose collars, and using antimicrobial cleansers, are also incorporated into the treatment plan to help maintain remission and prevent flares.