Tinea capitis in Hainan: a prospective study

Abstract

Objective: Tinea capitis, a chronic inflammatory disease of the scalp and hair shafts caused by dermatophyte infections, ​manifests clinically​ as erythematous lesions, scaling, alopecia, and pustule formation. Hainan, a tropical island province in China, exhibits distinctive climatic conditions and demographic contact patterns that ​could shape​ its pathogen spectrum. However, comprehensive epidemiological data ​remain scarce. This study ​analyzes​ the epidemiological characteristics and pathogen spectrum of tinea capitis in Hainan, China.

Methods: This study ​was undertaken​ across 11 coastal and inland dermatological centers in Hainan Province (January 2023 to December 2024). A total of 76 tinea capitis patients ​diagnosed​ via mycological examination (fungal fluorescence microscopy, fungal culture with species identification) ​and corroborated​ by dermatoscopic evaluation ​were consecutively enrolled. Data on demographic characteristics, exposure history, and clinical manifestations ​were systematically collated​ using standardized case report forms. Pathogen subtyping ​was performed via​ integrated morphological identification ​supplemented by​ molecular biological analysis of the ITS region.

Results: Among 76 enrolled patients, minors (≤15 years) ​accounted for​ 80.26% (61/76), with ≤10-year-olds ​representing​ 91.8% (56/61) of pediatric cases. The overall male-to-female ratio ​was recorded as​ 1:1.05 (37 males vs. 39 females), while pediatric patients (≤15 years) ​exhibited​ a 1.07:1 ratio (31 males vs. 29 females). Animal contact history ​was reported in​ 31 cases (40.79%), scalp trauma in 3 cases (3.95%), and co-occurring superficial fungal infections in 12 cases (15.79%). ​Fungal elements were detected​ via direct microscopic examination in 64 cases (84.21%). Fungal cultures ​obtained​ 45 positive isolates (19 strains in 2023, 26 in 2024), with kerion (inflammatory tinea capitis) ​exhibiting​ the highest culture positivity rate, followed by tinea alba. ​The primary pathogens identified​ were zoophilic Microsporum canis (M. canis) (20 cases, 43.79%) and anthropophilic Trichophyton rubrum (T. rubrum) (9 strains, 19.57%). Clinical manifestations ​comprised​ kerion (44 cases, 57.89%), tinea alba (27 cases, 35.53%), and black dot tinea (5 cases, 6.58%). Kerion cases ​were predominantly linked to​ M. canis and T. mentagrophytes (interdigital subtype), whereas tinea alba ​demonstrated​ infections by M. canis and T. rubrum. Black dot lesions ​were additionally observed​ in M. canis infections.

Conclusion: The primary affected group is children ≤10 years old, with the most common pathogenic fungus being zoophilic M. canis, and clinical classification is predominantly kerion. Dermatologists should pay attention to different transmission routes and pathogen spectra.

Keywords: epidemiology; microsporum canis; pathogenic fungi; prospective; tinea capitis.

Figure 1

Types of Tinea capitis (A) Kerion: one to several round, erythematous, infiltrative, or raised inflammatory plaques with surface clusters of follicular micropustules, honeycomb-like follicular openings, and expressible purulent discharge upon pressure. Hairs in the affected area are loose and easily extracted. (B) Tinea alba: Scalp lesions present as gray-white scaly patches, round or oval in shape, with possible satellite lesions. (C) Black dot ringworm: Affected hairs break off at the follicular orifice, leaving black, dot-like remnants at the follicular openings.

Figure 2

Types and pathogenic bacteria of tinea capitis.

Figure 3

Pathogen composition in 2023 and 2024.

Figure 4

Pathogen species and age groups.