Acne keloidalis nuchae

Management Strategy

Effective management starts with an accurate diagnosis. AKN is diagnosed clinically by the presence of inflammatory papules, pustules, and scar-like lesions on the occipital scalp and posterior neck of males with Afro-textured hair. Rarely, AKN occurs in females or individuals of non-African descent. The diagnosis is made clinically, without need for biopsy in the vast majority of cases. Characteristic histopathologic features include acute and chronic folliculitis, ruptured pilosebaceous units, and dermal fibrosis. When pustules, scale, or crust is present, bacterial and fungal cultures aid to rule out bacterial folliculitis and/or superinfection, or tinea capitis, respectively. Pustules due to Staphylococcus aureus folliculitis can resemble early AKN, but are more superficial, lack induration or keloid-like features, and respond rapidly to appropriate antibiotics.

Treatment of AKN requires suppressing active inflammation and fibrosis as well as avoidance of exacerbating factors using a combination of medical therapies, procedural interventions, and behavioral modification. Disease management is heavily based on clinician experience due to limited evidence or controlled studies and lack of consensus guidelines.

The initial approach comprises avoidance of close shaving, friction, and rubbing to prevent disease exacerbations in combination with medical treatments. Mild disease is managed with a combination of topical therapies including high-potency topical corticosteroids (group 1 or 2, e.g., clobetasol 0.05% gel or foam), antimicrobial washes (e.g., chlorhexidine wash), topical antibiotics (e.g., clindamycin phosphate 1% gel or foam), and topical retinoids (e.g., tazarotene 0.05% or 0.1% gel). Topical corticosteroids are applied once or twice daily and alternating in 2-week cycles to minimize effects of chronic steroid use. Twice daily application of clobetasol propionate 0.05% foam in alternating 2-week cycles was shown to be effective in a 20-subject, open-label, clinical trial. Improvement is typically achieved in 6–8 weeks and therapy is continued until signs (e.g., papules/pustules) and symptoms (e.g., pruritus, pain) have improved, with reinitiation of therapy for flares. This author (AFA) favors clobetasol propionate 0.05% foam twice daily or a fixed combination halobetasol 0.01%-tazarotene 0.045% lotion once daily for 2 weeks followed by application three times weekly.

Antimicrobial washes including chlorhexidine and povidone iodine are used to prevent secondary infection. If superinfection is suspected, cultures and appropriate antibiotic therapy should be completed prior to initiating steroids. When pustules are present, topical antibiotics are recommended. No formal studies have been completed to evaluate the efficacy of topical antibiotics for AKN. This author (AFA) favors topical clindamycin 1% gel or foam for treatment of mild pustules . Efficacy of once-daily topical retinoids, including adapalene, tretinoin, and tazarotene, is unclear, though they are theorized to improve AKN through antiinflammatory effects and prevention of follicular occlusion.

Persistent inflammatory lesions as well as keloid-like scars of AKN can be effectively treated with intralesional triamcinolone at varying concentrations ranging from 2.5 to 40 mg/mL with higher concentrations (>20 mg/mL) reserved for large (>3 cm), keloid-like lesions. Cryosurgery has also been used successfully, though no studies have evaluated specific parameters for AKN, and hypopigmentation or depigmentation are risks in patients with skin of color.

Failure of the above therapies or moderate-to-severe disease warrants systemic treatments. Oral antibiotics are used for several weeks to months to control inflammatory flares. Tetracyclines such as doxycycline or minocycline are the mainstay of oral antibiotic therapy of AKN; however, published evidence is limited. This author (AFA) favors oral doxycycline for its antiinflammatory and antimicrobial effects. When Staphylococcus aureus superinfection is present, a course of a first-generation cephalosporin or doxycycline at antimicrobial doses (50–100 mg twice daily) is recommended. As an adjunct to topical and intralesional therapy, subantimicrobial doxycycline (40m g/day) for 12–16 weeks is useful in this author’s experience. Select cases show effective treatment of refractory inflammatory lesions with oral retinoids starting at 0.25–0.6 mg/kg daily followed by lower doses for maintenance.

Light and energy based therapies are effective for long-term disease control. Long-pulse, long-wave lasers including alexandrite 755 nm, diode 800–810 nm, and neodymium:yttrium-aluminum-garnet (Nd:YAG) 1064 nm are effective treatment for AKN due to their ability to completely destroy the hair follicle. The 1064-nm Nd:YAG laser has the most favorable profile for hair removal in darker-skinned patient populations: deepest penetration and least absorption by melanin, thereby maximizing efficacy and minimizing risk of dyspigmentation. Its efficacy has been demonstrated in a prospective controlled trial. Er:YAG has been shown to have the same efficacy as Nd:YAG for papular disease as well as beneficial effects on larger plaques in a comparative trial. A 12-subject AKN trial showed targeted ultraviolet B ( UVB) phototherapy administered three times weekly is effective and well tolerated.

Surgical excision, including scalpel, electrosurgical, or laser excision, followed by primary closure or secondary intention healing is effective for refractory and severe disease. Regardless of the surgical technique utilized, successful treatment requires complete removal of hair follicles to prevent recurrence. Horizontal ellipse excision followed by secondary intention healing is recommended for optimal cosmetic outcomes. Postsurgical adjuvant therapies have included intralesional or topical steroids and radiotherapy; however, these are not indicated given the low recurrence rate. Local radiation therapy with 3 Gy and 6 MeV × 10 sessions on alternating days was successful in treating a case of refractory AKN that recurred after therapy with topicals, oral antibiotics, isotretinoin, and partial excision.