Abstract Context: The diagnostic accuracy of ultraviolet fluorescent (UVF) dermoscopy in identifying dermatophyte infection remains to be elucidated. Aims: to assess the dermoscopic features and diagnostic accuracy of UVF dermoscopy in tinea capitis and tinea of other parts of the skin. Settings and Design: A cross-sectional comparative study was performed on 119 dermatophytosis cases. Methods and Materials: Fifty-one cases of tinea capitis and 68 cases of tinea of other sites. Dermoscopic examination was performed using both polarized and UV-induced fluorescence settings. Then, scales along the lesion’s edge were scraped, and fluorescent hair was plucked for microscopic examination with KOH. Results: For tinea capitis, ectothrix hair invasion was found in 45 (88.2%) cases, and endothrix in 6 (11.8%) cases. Polarized dermoscopy findings in ectothrix were Morse code-like hair (93.3%), zigzag hair (23.5%), and whitish sheath (17.8%), while corkscrew and comma hairs were found in endothrix. UVF dermoscopy showed peripilar green fluorescence in all cases with ectothrix hair, with a sensitivity of 88.2% and a positive predictive value of 100%. In tinea of other sites, the main dermoscopic findings were white scales in 70.6% of cases peripherally, 47.1% perifollicular, and 8.8% within skin furrows. 53% of lesions showed evidence of damaged hair. In the UVF setting, peripilar green fluorescence was observed in 44.1% of vellus hair. The sensitivity and positive predictive value of UVF dermoscopy were 44.1% and 100%, respectively. Conclusions: UVF dermoscopy accurately discriminates between endothrix and ectothrix hair in tinea capitis and identifies vellus hair involvement in tinea of other parts of the skin.
Ahmed et al. (Thu,) studied this question.