Optical Coherence Tomography in the Evaluation of the Scalp and Hair: Common Features and Clinical Utility

Early diagnosis and treatment of hair loss disorders is vital in providing patients with improved psychological outcomes. Non-invasive imaging with optical coherence tomography (OCT) may be useful in characterizing and managing alopecia. Despite expanding clinical applications of OCT in dermatology, guidelines demonstrating in vivo features of normal and alopecic scalp images remain scant. This pilot study aims to provide an atlas of OCT findings of healthy and alopecia subjects, explore diagnostic quantitative endpoints of alopecia, and compare epidermal thickness and follicular density between scalp regions.

A total of 32 patients (19-76 years old) were enrolled in the study, including healthy patients (n = 6), and patients with scarring alopecia (n = 12) or non-scarring alopecia (n = 14). An in-line fiber-based swept source OCT was used to image five scalp locations at baseline and 6-month visits. Three investigators evaluated each image for gross features, epidermal thickness, and follicular density.

Only data from baseline imaging analysis is discussed in this manuscript. Qualitative differences of OCT images are identified in sample images from healthy scalp and each subtype of alopecia studied. Scarring alopecia is characterized by significantly increased epidermal thickness (average Image J pixel units 32 ± 2 compared with non-scarring alopecia [average 28 ± 3] and control [average 27 ± 3]) (P = 0.022) and decreased follicle count (average 35 ± 5 in a 5 × 7 mm² area compared with control (50 ± 3) and non-scarring patients (47 ± 6)) (P = 0.0052). Scalp location had no impact on epidermal thickness (P = 0.861) or follicular density (P = 0.15).

OCT holds promise as a non-invasive technique to further characterize and objectively measure alopecia. Larger sample sizes and longitudinal data are needed to improve reliability and determine if additional distinction between alopecia subtypes and treatment monitoring is possible. Lasers Surg. Med. © 2020 Wiley Periodicals, Inc.