PIILIF Present in Patients With Acne Keloidalis Nuchae

Perifollicular infundibulo-isthmic lymphocytoplasmic infiltrates and fibrosis (PIILIF) may be a precursor to other primary cicatricial alopecias, including acne keloidalis nuchae (AKN) and folliculitis decalvans (FD). In a study, researchers found that all patients with AKN also showed histologic evidence of PIILIF.¹

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In 41 male patients (mean age 34.2 years) with AKN seen at a Los Angeles clinic between June and December 2022, normal-appearing-scalp (NAS) zones were biopsied. Twenty patients were of African descent, 17 were Hispanic, and 4 were European-descended.

Trichoscopy-selected points with perifollicular erythema or cast scaling were biopsied a minimum of 5 cm away from AKN-affected zones and histologic analysis was performed. A diagnosis of AKN or FD was made by clinical examination or based on prior histopathology reports. The most common trichoscopy indicator of PIILIF is perifollicular erythema, with or without scales.

Histological features of PIILIF were seen in all specimens taken from NAS zones, with 96% exhibiting vellus or miniaturized hair absence. Prior treatments for AKN included surgery (40%), laser hair removal (24%), or topical multimodal solutions (38%). In 36% of patients, there was a history of AKN recurrence or disease expansion.

Most of the patients did not know of disease presence in their NAS zones, but 60% reported itchiness and 44% assumed seborrheic dermatitis was present or received treatment for it. None of the patients exhibited seborrheic dermatitis on histologic examination. Symmetric hair loss clinically consistent with androgenic alopecia (AGA) was seen in 1/3 of patients.

Umar et al’s findings of PIILIF in trichoscopy-guided biopsies of NAS zones of all AKN patients support a strong correlation between PIILIF and AKN and a subclinical disease state of PIILIF prior to AKN. The patients had no history of using chemical texturizers, hot combs, braiding, or other traumatic hair grooming practices.

“Our findings suggest that the absence of vellus or miniaturized hair is a more consistent finding than sebaceous gland reduction in AKN-associated PIILIF. Furthermore, the significant difference in sebaceous gland loss between AKN (75%) and PIILIF (42%) biopsies suggests that the destruction of vellus/miniaturized hairs is an earlier feature of AKN than sebaceous gland destruction, which occurs after the disease is fully established.”

PIILIF was seen in NAS zones of all patients with combined AKN-FD, suggesting that PIILIF may be a precursor to both AKN and FD.

None of the 4 White men in the study were aware that they had AKN, suggesting the condition may be more prevalent in that population than previously reported. Incidence of AKN was similar in Hispanics (41%) and men of African descent (49%), supporting reports that AKN is common among men of color.

The authors concluded that “an emphasis on early diagnosis and expanded treatment approaches directed at inflammatory scalp-wide diseases (eg, steroids, tetracyclines, or biologics) are necessary for all patients.”

Reference

1. Umar S, Ton D, Carter MJ, Shitabata P. Unveiling a shared precursor condition for acne keloidalis nuchae and primary cicatricial alopecias. Clin Cosmet Investig Dermatol. Published online August 25, 2023.(16)2315-2327. doi:10.2147/CCID.S422310