Tinea capitis: dermoscopy and calcium fluorescent microscopy as highly efficient and precise diagnostic tools

Tinea capitis comprising of tinea favosa and kerion is mostly seen in school-aged children. Some tinea capitis often presented with insignificant findings under the naked eyes are easily overlooked. The authors describe an unusual case of tinea capitis caused by Trichophyton violaceum. The patient was an 8-year-old girl, with a history of pruritus on the scalp for more than one year. A diagnosis of tinea capitis was confirmed by clinical examination aided by dermoscopy, calcium fluorescent microscopy and culture. Comma and corkscrew hairs are two specific dermoscopic patterns of tinea capitis. The patient was treated with systemic itraconazole, topical application with 1% naftifine 0.25% ketoconazole cream followed after daily hair wash with 2% ketoconazole shampoo for 8 weeks.


Introduction
Tinea capitis comprising of tinea favosa and kerion is mostly seen in school-aged children. The incidence of unusual findings of tinea capitis caused by anthropophilic dermatophytes, such as Trichophyton violaceum, has grown in recent years. These fungi tend to cause scarce inflammatory reac-ଝ How to cite this article: Xiao H, Pradhan S, Ran X, Ran Y. Tinea capitis: dermoscopy and calcium fluorescent microscopy as highly efficient and precise diagnostic tools. An Bras Dermatol. 2020;95:332---5. *

Case report
An 8-year-old Chinese girl weighing 21 kg presented to the dermatology clinic with a history of pruritus on the scalp for more than one year. Her past medical history was unremarkable. She had a history of taming a cat and a dog at home. Dermatological examination revealed a small beansized patch hair loss and scattered ''black spots'' on the top of the head (Fig. 1). Numerous short, highly convoluted, coiled, and twisted corkscrew hairs were observed under polarized dermoscopy (JD801D; JEDA, China) (Fig. 2). Calcium fluorescent (Fungal Fluorescence Detection Kit, Jiangsu Lifetime Biological Technology Co., Ltd.) microscopy of the scale in corkscrew hair revealed extremely high numbers of spores (Fig. 3). The lush purple colony developed after inoculating the scales in SDA medium at 28 • C for 30 days (Fig. 4). Calcium fluorescent microscopic examination showed separate branches of mycelium with irregular protrusions, and thick-walled spores of varying sizes after the colony were cultured in PDA medium at 25 • C for 14 days (Fig. 5). The girl was diagnosed with an unusual case of tinea capitis caused by T. violaceum confirmed by dermoscopy, calcium fluorescent microscopic examination and culture. She received systemic treatment with itraconazole (Xian-Janssen Pharmaceutical Ltd.), 100 mg per day with full fatty milk, combined with topical application of 1% naftifine 0.25% ketoconazole cream (Chongqing Huapont Pharmaceutical Co., Ltd.) followed after daily hair wash with 2% ketoconazole shampoo (Triatop, Xian-Janssen Pharmaceutical Ltd.). The patient showed drastic improvement after 8 weeks of treatment with the disappearance of corkscrew hairs. Therefore, no recurrence was observed after one year of follow-up (Fig. 6).

Discussion
The previous study speculated the formation of corkscrew hairs as a result of a combination of internal damage due to unsymmetrical hair degradation by T. violaceum and external resistance due to scales covering the hair. 3 Dermoscopy is a diagnostic tool for the identification of fine structures and colors that cannot be observed with the naked eye. It can facilitate the diagnosis of tinea capitis as a rapid, noninvasive, reliable, and an inexpensive method. Calcium fluorescent microscopy is easy to operate and timely that accurately identifies the fungal infections by specific staining of the fungal cell wall. Thus, it can significantly improve its positive rate, on special populations,

Financial support
None declared.

Authors' contributions
Hui Xiao: Statistic analysis; approval of the final version of the manuscript; conception and planning of the study; elaboration and writing of the manuscript; obtaining, analysis, and interpretation of the data; effective participation in research orientation; intellectual participation in the propaedeutic and/or therapeutic conduct of the studied cases; critical review of the literature; critical review of the manuscript.  Sushmita Pradhan: Statistic analysis; approval of the final version of the manuscript; conception and planning of the study; elaboration and writing of the manuscript; obtaining, analysis, and interpretation of the data; effective participation in research orientation; intellectual participation in the propaedeutic and/or therapeutic conduct of the studied cases; critical review of the literature; critical review of the manuscript.
Xin Ran: Elaboration and writing of the manuscript; obtaining, analysis, and interpretation of the data; effective participation in research orientation; intellectual participation in the propaedeutic and/or therapeutic conduct of the studied cases; critical review of the manuscript.
Yuping Ran: Statistic analysis; approval of the final version of the manuscript; conception and planning of the study; elaboration and writing of the manuscript; obtaining, analysis, and interpretation of the data; effective participation in research orientation; intellectual participation in the propaedeutic and/or therapeutic conduct of the studied cases; critical review of the literature; critical review of the manuscript.

Conflicts of interest
None declared.