Application of Ultraviolet-Induced Fluorescence Trichoscopy (UVFT) in Hair and Scalp Diseases.

Introduction: Ultraviolet-induced fluorescence dermoscopy (UVFD) is increasingly utilized in dermatooncology and general dermatology. The objective of the study was to characterize the ultraviolet-induced fluorescence trichoscopy (UVFT) findings in a wide range of hair and scalp conditions.

Methods: Consecutive patients with non-scarring alopecias (alopecia areata, AA, n = 40; androgenetic alopecia, AGA, n = 40), scarring alopecias (frontal fibrosing alopecia, FFA, n = 20; lichen planopilaris, LPP, n = 20; folliculitis decalvans, FD, n = 14; discoid lupus erythematosus, DLE, n = 23), and inflammatory scalp conditions (psoriasis, n = 30; seborrheic dermatitis, n = 14) were included. Examinations were performed using polarized trichoscopy and UVFT.

Results: The following features were observed under UVFT: white-blue perifollicular fluorescence, white-blue interfollicular fluorescence, irregular confluent dark areas, dark follicular dots, dark perifollicular areas, regular/irregular pink-red follicular fluorescence, regular/irregular green follicular fluorescence, short white hair, black dots, exclamation mark hair, double/triple white follicular dots, pink-red fluorescence of the scales, pink-red fluorescence of the background. Non-scarring alopecias showed more frequently pink-red or green follicular fluorescence (p < 0.001), dark follicular dots (p < 0.001), short white hair (p < 0.001), and double/triple white follicular dots (p < 0.001). In scarring alopecias, white-blue perifollicular fluorescence (p < 0.001), dark perifollicular areas (p < 0.001), and dark confluent areas (p < 0.001) were more commonly observed. Psoriasis showed more frequently pink-red fluorescence of the scales than seborrheic dermatitis (p = 0.019).

Conclusion: UVFT supports the differentiation between scarring and non-scarring alopecia, as well as between psoriasis and seborrheic dermatitis. UVFT may hypothetically facilitate the biopsy site selection by highlighting the subclinical perifollicular and interfollicular inflammation.