The patient was given a diagnosis of acne keloidalis nuchae (AKN), a chronic folliculitis that is characterized by smooth, dome-shaped papules on the posterior scalp and neck that become confluent and form firm papules and hairless, keloid-like plaques. Seen almost exclusively in young, postpubescent African American males, the condition is often asymptomatic, although some patients complain of itching at the affected area.
The cause of AKN may be associated with an acute pseudofolliculitis secondary to close-shaved curly hair reentering the skin; this leads to a foreign body reaction to hair protein and subsequent fibrosis. AKN is diagnosed based on the appearance and location of the papules, as well as the patient’s history.
Treatment of AKN is often difficult, but early treatment decreases the potential of developing larger lesions and long-term disfigurement. Topical steroid therapy is indicated for mild to moderate AKN. Application of tretinoin 0.01% gel once or twice daily for several months has an anti-inflammatory effect and alters keratinocyte differentiation, which may discharge ingrown hairs. Topical and systemic antibiotics minimize infection associated with pseudofolliculitis and have anti-inflammatory effects. Intralesional steroid injections (triamcinolone acetonide 2.5-5 mg/cc) with 0.1 cc injected into each lesion every 2 to 3 weeks for 3 to 6 injections can reduce inflammation and pruritus and reduce the thickness of keloidal scars. (For a how-to video that illustrates intralesional injections, go to http://www.mdedge.com/jfponline/article/88050/dermatology/intralesional-injections.)
Surgical management is generally reserved for large lesions that do not respond to medical management. The use of CO2 laser ablation can be considered for advanced cases.
Patients with AKN can prevent further irritation of the affected area by not wearing anything on their head that rubs on the involved area. Patients should also refrain from shaving the posterior scalp and neck to prevent the pseudofolliculitis that may be causing this condition. Electric barber trimmers that leave a short stubble (but do not cleanly shave the skin) are OK.
In this case, the patient’s papules flattened and became asymptomatic over several months of treatment with tretinoin 0.01% gel, doxycycline 100 mg/d, and a series of biweekly intralesional steroid injections. A flat-scarred patch remained.
Adapted from: Rafferty E, Brodell R. Occipital scalp papules in a teenage boy. J Fam Pract. 2014;63:739-740.