ABSTRACT
Acne keloidalis/acne kleoidalis nuchae (AKN), also known as folliculitis keloidalis, is a primary neutrophilic cicatricial alopecia that mostly occurs in men of African, African American and Afro-Caribbean origin with coarse curly hair, and is characterized by chronic follicular papules mainly on the occipital scalp and neck that evolve into keloid-like scars and permanent alopecia.
The name “keloidalis” is a misnomer as the lesions do not show keloidal features on histology and the patients do not have tendency to develop keloids in other parts of the body.
The onset after puberty and the exclusive predilection for the male sex suggest a hormonal component in the pathogenesis.
It is believed that chronic local mechanical irritation to the nuchal and the occipital area, by frequent shaving, picking or friction to hair that is kinky, leads to follicular irritation, exposure to follicular alloantigens that evoke an immune response with inflammation, follicular destruction and transepidermal elimination of the hair shafts in the dermis. This leads to further chronic inflammation with granulomas. The reparative attempts in predisposed individuals result in abnormal hypertrophic scarring and permanent alopecia.
Metabolic syndrome (present in 61% of the patients as per a recent study) and chronic infection (Demodex, Staphylococcus, Malassezia) may play a secondary role in the pathogenesis.
Early lesions: Flesh-colored or erythematous papules, with pustules on the occipital scalp and the posterior part of the neck that may extend into the vertex (Figure 22.1). The lesions are accompanied by itch or pain. Erythematous papules, with pustules on the occipital scalp. (Courtesy of Giselle Martins, MD; reprinted with permission from Katoulis A, Ioannides D, Rigopoulos D, eds., <italic>Hair Disorders: Diagnosis and Management</italic>, CRC Press: Boca Raton and Abingdon, forthcoming 2021.) https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig22_1.tif"/>
Late lesions: Sclerotic plaques, nodules and keloidal masses with sinus tracts, and devoid of hairs (cicatricial alopecia) (Figure 22.2). Folliculitis keloidalis resulting in patchy hairless cicatricial alopecia on the vertex. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig22_2.tif"/>
Androgenetic alopecia, central centrifugal cicatricial alopecia and folliculitis decalvans have been reported in association with AKN.
147On trichoscopy the features depend on the stage:
Early stage shows folliculocentric pink papules and pustules with a red rim and white streaks (Figure 22.3) and crown vessels (Figure 22.4), which correspond to chronic inflammatory infiltrate and perifollicular fibrosis; broken hairs and peripilar casts ensue from the follicular destruction. Early AKN: folliculocentric papules with a red rim (×40). (Courtesy of Giselle Martins, MD; reprinted with permission from Katoulis A, Ioannides D, Rigopoulos D, eds., <italic>Hair Disorders: Diagnosis and Management</italic>, CRC Press: Boca Raton and Abingdon, forthcoming 2021). https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig22_3.tif"/> Folliculocentric papules with crown vessels (×60). (Courtesy to Giselle Martins, MD.) https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig22_4.tif"/>
Later stage shows white follicular papules, white patches at the site of loss of follicular openings and irregular pinpoint white dots (Figure 22.5). Intact hair follicles at the margins may exhibit tufting. These late lesions show white folliculocentric papules and irregular pigmented network (×20). (Reprinted with permission from Katoulis A, Ioannides D, Rigopoulos D, eds., <italic>Hair Disorders: Diagnosis and Management</italic>, CRC Press: Boca Raton and Abingdon, forthcoming 2021.) https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429457609/a1a07c34-5530-453d-aca4-02e4ee680a4a/content/fig22_5.tif"/>
