Follicular keratosis of the chin treated with 1.24R-dihydroxyvitamin D3 ointment

Follicular keratosis of the face in pediatric patients of color

BACKGROUND/OBJECTIVES

Follicular keratosis (FK) is a poorly understood disorder presenting with multiple, grouped hyperkeratotic follicular papules typically affecting the chin or jawline. This study describes the clinical presentation, histopathology, management, and outcomes of a series of pediatric patients of color with FK of the face, thought to be related to rubbing or friction on the skin.

METHODS

Retrospective review of 20 pediatric patients with FK of the face who presented to our pediatric dermatology practice between April 2019 and October 2021.

RESULTS

Twenty patients (mean age 12.1 years, 13 females), all self-identified as Black/African American, were included. All presented with an initially asymptomatic, hyperpigmented patch containing multiple hyperkeratotic follicular papules, located on the cheek, chin, upper lip, and/or jawline. Five patients endorsed a history of rubbing the site. Nine patients had onset of the lesions during the COVID-19 pandemic. Treatments included topical vitamin D analogs, corticosteroids, and/or retinoids. Topical vitamin D analogs and retinoids improved the texture and hyperpigmentation of the follicular lesions in only four patients, while topical corticosteroids had no effect. Histopathological examination of two patients revealed multiple dilated follicles containing keratinized material and associated with a sparse dermal inflammatory infiltrate in one patient and granulomatous inflammation within the dermis in the other.

CONCLUSIONS

In our cohort of pediatric patients with FK, patients of color were preferentially affected, and all cases were associated with hyperpigmentation. Some patients presented during the COVID-19 pandemic suggesting that friction from facial mask wearing may have induced or exacerbated this uncommon condition.

Familial occurrence of follicular keratosis of the chin

Follicular keratosis of the chin is a rare and poorly understood pediatric disorder with a characteristic presentation of multiple follicular papules on the chin. Although prolonged friction or pressure over the chin is considered an etiology, such history is not present in most cases. It sometimes occurs within families without any evidence of physical trauma, suggesting a genetic predisposition of the patients to develop the disease. In the present study, we report two brothers with the disease, in whom no definite physical trauma was identified but comedo formation was evident. The clinical presentation of follicular keratosis of the chin is unique, particularly owing to its specific location on the chin with an age predilection from late childhood to puberty. We assume that the hormone status is an etiology of the disease since the chin is an area where androgenic hormones target at puberty and comedogenesis is a well-known biological function of the hormone. We also assumed that the susceptibility to the hormone may involve in the development of the familial follicular keratosis of the chin.

Follicular disorders of the face

Follicular disorders are possibly a commonly seen, though rarely reported, group of disorders, which are localized around follicles and appendages and clinically present as small papules. Classically, clinicopathological follicular plugging is seen in the "true" follicular disorders, which are appropriately referred to as follicular keratosis. Another subtype is folliculitis (infectious or noninfectious) and the follicular mimickers that clinically resemble "true" follicular disorders without the follicular keratoses. Acne vulgaris has an amalgamation of all the above lesion types. Our review is aimed at describing all the follicular disorders and gives an algorithm for diagnosing the common follicular disorders.