Optical coherence tomography-assisted diagnosis of follicular keratosis of the chin

Confocal microscopy and optical coherence tomography of inflammatory skin diseases in hairs and pilosebaceous units: A systematic review

Common skin disorders such as acne vulgaris, rosacea and folliculitis are bothersome prevalent inflammatory diseases of hair follicles that can easily be investigated bedside using optical coherence tomography (OCT) and reflectance confocal microscopy (RCM) with micrometre resolution, opening a novel era for high-resolution hair follicle diagnostics and quantitative treatment evaluation. EMBASE, PubMed and Web of Science were searched until 5 January 2023 to identify all studies imaging hair follicle characteristics by RCM and OCT for diagnosis and monitoring of treatment in hair follicle-based skin disorders. This study followed PRISMA guidelines. After inclusion of articles, methodological quality was assessed using the QUADAS-2 critical appraisal checklist. Thirty-nine in vivo studies (33 RCM and 12 OCT studies) were included. The studies focused on acne vulgaris, rosacea, alopecia areata, hidradenitis suppurativa, folliculitis, folliculitis decalvans, lichen planopilaris, discoid lupus erythemasus, frontal fibrosing alopecia and keratosis pilaris. Inter- and perifollicular morphology including number of demodex mites, hyperkeratinization, inflammation and vascular morphology could be assessed by RCM and OCT in all included skin disorders. Methodological study quality was low, and interstudy outcome variability was high. Quality assessment showed high or unclear risk of bias in 36 studies. Both RCM and OCT visualize quantitative features as size, shape, content and abnormalities of hair follicles, and have potential to support clinical diagnosis and evaluate treatment effects. However, larger studies with better methodological quality are needed to implement RCM and OCT directly into clinical practice.

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.

Two optical coherence tomography systems detect topical gold nanoshells in hair follicles, sweat ducts and measure epidermis

Optical coherence tomography (OCT) is an established imaging technology for in vivo skin investigation. Topical application of gold nanoshells (GNS) provides contrast enhancement in OCT by generating a strong hyperreflective signal from hair follicles and sweat glands, which are the natural skin openings. This study explores the utility of 150 nm diameter GNS as contrast agent for OCT imaging. GNS was massaged into skin and examined in four skin areas of 11 healthy volunteers. A commercial OCT system and a prototype with 3 μm resolution (UHR-OCT) were employed to detect potential benefits of increased resolution and variability in intensity generated by the GNS. In both OCT-systems GNS enhanced contrast from hair follicles and sweat ducts. Highest average penetration depth of GNS was in armpit 0.64 mm ± SD 0.17, maximum penetration depth was 1.20 mm in hair follicles and 15 to 40 μm in sweat ducts. Pixel intensity generated from GNS in hair follicles was significantly higher in UHR-OCT images (P = .002) and epidermal thickness significantly lower 0.14 vs 0.16 mm (P = .027). This study suggests that GNSs are interesting candidates for increasing sensitivity in OCT diagnosis of hair and sweat gland disorders and demonstrates that choice of OCT systems influences results.