Aetiology of tinea capitis in China: a multicentre prospective study.

BACKGROUND: Tinea capitis is still common in developing countries, such as China. Its pathogen spectrum varies across regions and changes over time. OBJECTIVES: This study aimed to clarify the current epidemiological characteristics and pathogen spectrum of tinea capitis in China. METHODS: A multicentre, prospective descriptive study involving 29 tertiary hospitals in China was conducted. From August 2019 to July 2020, 611 patients with tinea capitis were enrolled. Data concerning demography, risk factors and fungal tests were collected. When necessary, the pathogens were further identified by morphology or molecular sequencing in the central laboratory. RESULTS: Among all enrolled patients, 74·1% of the cases were in patients aged 2-8 years. The children with tinea capitis were mainly boys (56·2%) and were more likely than adults to have a history of animal contact (57·4% vs. 35·3%, P = 0·012) and zoophilic dermatophyte infection (73·5% vs. 47%). The adults were mainly female (83%) and were more likely than children to have anthropophilic agent infection (53% vs. 23·9%). The most common pathogen was zoophilic Microsporum canis (354, 65·2%), followed by anthropophilic Trichophyton violaceum (74, 13·6%). In contrast to the eastern, western and northeastern regions, where zoophilic M. canis predominated, anthropophilic T. violaceum predominated in central China (69%, P < 0·001), where the patients had the most tinea at other sites (20%) and dermatophytosis contact (26%) but the least animal contact (39%). Microsporum ferrugineum was the most common anthropophilic agent in the western area, especially in Xinjiang province. CONCLUSIONS: Boys aged approximately 5 years were the most commonly affected group. Dermatologists are advised to pay more attention to the different transmission routes and pathogen spectra in different age groups from different regions.

In vitro antifungal susceptibility of Trichophyton violaceum isolated from tinea capitis patients.

OBJECTIVES: Trichophyton violaceum is an anthropophilic dermatophyte that is endemic to parts of Africa and Asia and is sporadic in Europe. T. violaceum mainly causes tinea capitis in both children and adolescents. Although the infections caused by T. violaceum are of considerable medical importance, its antifungal susceptibility profile remains poorly examined. METHODS: In this study, we tested the in vitro antifungal susceptibility of a set of clinical T. violaceum isolates obtained from tinea capitis patients, using the CLSI broth microdilution method. We tested eight antifungals and used isolates collected from Western China (21), Eastern China (12), the Middle East (1), Europe (20), South Africa (7) and Canada (1). RESULTS: The geometric means of the MICs of the antifungals for all isolates were as follows (in increasing order): posaconazole, 0.021 mg/L; terbinafine, 0.023 mg/L; voriconazole, 0.062 mg/L; amphotericin B, 0.20 mg/L; itraconazole, 0.34 mg/L; caspofungin, 0.56 mg/L; fluconazole, 4.23 mg/L; and flucytosine, 8.46 mg/L. No statistically significant differences in the susceptibility profiles of T. violaceum were detected within the geographical regions tested. CONCLUSIONS: Posaconazole, terbinafine and voriconazole were shown to be the most potent antifungal agents against T. violaceum isolates obtained from tinea capitis patients worldwide. These results might help clinicians in developing appropriate therapies that have a high probability of successfully treating tinea capitis due to T. violaceum.

Evaluation of two molecular techniques for rapid detection of the main dermatophytic agents of tinea capitis.

BACKGROUND: Tinea capitis is very common in Western China, with the most widespread aetiological agent being Trichophyton violaceum, while Microsporum canis is prevalent in the remainder of China. Conventional diagnostics and internal transcribed spacer (ITS) sequencing analyses have proven relatively limited due to the close phylogenetic relationship of anthropophilic dermatophytes. Therefore, alternative molecular tools with sufficient specificity, reproducibility and sensitivity are necessary. OBJECTIVES: To evaluate two molecular techniques [multiplex ligation-dependent probe amplification (MLPA) and rolling circle amplification (RCA)] for rapid detection of the aetiological agents of tinea capitis, T. violaceum and M. canis. METHODS: Probes of RCA and MLPA were designed with target sequences in the rDNA ITS gene region. Strains tested consist of 31 T. violaceum, 22 M. canis and 24 reference strains of species that are taxonomically close to the target species. RESULTS: The specificity and reproducibility of RCA and MLPA in detection of T. violaceum and M. canis were both 100% in both species. Sensitivity testing showed that RCA was positive at concentrations down to 1·68 × 10(6) copies of DNA in the TvioRCA probe, and 2·7 × 10(8) copies of DNA in McRCA. MLPA yielded positive results at concentrations of DNA down to 1·68 × 10(1) copies in the TvioMLPA probe and 2·7 × 10(2) in McMLPA. CONCLUSIONS: The two techniques were sufficiently specific and sensitive for discriminating the target DNA of T. violaceum and M. canis from that of closely related dermatophytes. RCA and MLPA are advantageous in their reliability and ease of operation compared with standard polymerase chain reaction and conventional methods.

A random comparative study of terbinafine versus griseofulvin in patients with tinea capitis in Western China.

OBJECTIVE: To compare the efficacy and safety of terbinafine with griseofulvin in the treatment of tinea capitis in Western China. METHODS: Children (2-14 years of age) with clinically diagnosed and potassium hydroxide microscopy-confirmed tinea capitis were randomized into three groups: group GRI4 received 4 weeks of griseofulvin; group TBF2 received 2 weeks of terbinafine; and Group TBF4 received 4 weeks of terbinafine. Clinical and mycological evaluations were done in 0, 2, 4, and 8 weeks and 1 year after therapy started. The isolated pathogenic fungi were evaluated for in vitro susceptibility by detecting the minimal inhibitory concentration (MIC) against terbinafine, griseofulvin, itraconazole, and ketoconazole. RESULTS: The clinical effectiveness rate of GRI4, TBF2, and TBF4 were 100% (95% CI-confidence interval: 82-100%), 96.3% (95% CI: 81-100%), and 100%(95% CI: 85-100%), respectively, at week 8 and 100% after 1 year for the 3 groups; clinical cure rates were 84.2%(95% CI: 77-99%), 85.2%(95% CI: 71-98%), and 78.3%(95% CI: 61-95%), respectively, at week 8 and 100% after 1 year for all agents; mycological cure rates were 100%(95% CI: 74-100%), 95.0%(95% CI: 74-100%), and 94.1%(95% CI: 50-93%) at week 8 and 100% after 1 year for the 3 groups. In vitro, all patient-derived cultures were sensitive to the four antifungal agents. CONCLUSION: Data from the clinical trial and in vitro antifungal activity indicated that terbinafine is efficacious and well tolerated in the treatment for Trichophyton infections (T. violaceum; Arthroderma vanbreuseghemii; and T. tonsurans) of the scalp, i.e., a 2- to 4-week course of terbinafine is as effective as a 4-week course of griseofulvin; in fact, a 2-week course of terbinafine is sufficient. Terbinafine is an effective alternative to griseofulvin against tinea capitis of Trichophyton infections.