Unveiling a Shared Precursor Condition for Acne Keloidalis Nuchae and Primary Cicatricial Alopecias

Abstract

Purpose Small observational studies suggest subclinical disease occurrence in the normal-appearing scalp zones of several primary cicatricial alopecias. To aid patient management, we began routinely evaluating the entire scalp of patients with acne keloidalis nuchae (AKN), including trichoscopy-guided biopsies. Patients and Methods This retrospective study evaluated 41 patients sequentially presenting with AKN at a single clinic between June and December 2022. Primary lesions and normal-appearing scalp in the superior parietal scalp at least 5 cm away from AKN-affected zones were clinically evaluated, and areas showing perifollicular erythema or scales/casts on trichoscopy were biopsied and histologically analyzed. Results Forty-one men with AKN, including 20 men of African descent, 17 Hispanic, and 4 European-descended Whites, were evaluated. All patients, including 22% with associated folliculitis decalvans, showed scalp-wide trichoscopy signs of perifollicular erythema or scaling in normal-appearing scalp areas. All patients showed histologic evidence of perifollicular infundibulo-isthmic lymphocytoplasmic infiltrates and fibrosis (PIILIF), with 96% showing Vellus or miniaturized hair absence. PIILIF was often clinically mistaken for seborrheic dermatitis (44–51%). All White patients had mild papular acne keloidalis nuchae lesions mistaken for seborrheic dermatitis. Conclusion PIILIF may be a precursor to a wide spectrum of primary cicatricial alopecias, including AKN and folliculitis decalvans. This finding carries implications for the early diagnosis and management of AKN and other primary cicatricial alopecias.

Refractory Folliculitis Decalvans Treatment Success with a Novel Surgical Excision Approach Using Guarded High-Tension Sutures

“…The association of FD with AKN is well established with studies, including two published by the lead author reporting a 7-24% association and suggesting a possible common pathoetiology. [16][17][18] Three out of five patients in our cohort had separate AKN lesions in their nape zones that were treated by either an electrosurgical knife or punch excision (Table 1). Furthermore, the presence of an LPP-like disease in the remaining non-FD scalp is a recognized phenomenon [19][20][21] and may influence prognosis; this should be investigated in all FD patients using trichoscopy and histology and treated as a separate entity when found.…”

“…High-tension sutures were removed once they became lax owing to wound contraction, typically between 4-6 weeks, with the option of retightening at 4 weeks. The remaining scalp was assessed for commonly associated conditions such as acne keloidalis nuchae (AKN) [16][17][18] and scalp-wide histologic evidence of perifollicular infundibuloisthmic lymphocytic infiltrates and fibrosis, an lichen planopilaris (LPP)-like condition [19][20][21] These conditions were treated separately after completing FD treatment.…”

Comorbidities and Treatment Options for Acne Keloidalis Nuchae

“…PIILIF has also been found in areas of AKN outside the scalp and other primary cicatricial alopecia conditions. Tus, the authors propose that PIILIF could be a unifying condition between these diseases [13].…”

“…Recently, in a study of 41 patients with AKN, perifollicular infundibulo-isthmic lymphocytoplasmic infltrates and fbrosis (PIILIF) was observed in 100% of patients and could be a subclinical precursor of AKN [13]. Te authors suggest that based on various infuences, such as lesion location, hormones, and trauma, PIILIF progresses to AKN.…”