Tinea capitis is caused by dermatophytic fungi, which thrive in keratinized tissues such as hair and nails. Common causative species include Trichophyton and Microsporum. These fungi can be transmitted through direct contact with infected individuals or animals, as well as through contact with contaminated objects like combs, towels, and bedding. The fungi can remain viable on these surfaces for extended periods, facilitating the spread of infection.
Fungal Species
Dermatophytes can be categorized based on their preferred hosts:
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Anthropophilic Species (Human Preference):
- Trichophyton tonsurans: Common in the United States.
- Trichophyton violaceum: Seen in individuals from Africa or the Middle East.
- Trichophyton soudanense, Trichophyton schoenleinii, Trichophyton rubrum, and Microsporum audouinii are other examples.
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Zoophilic Species (Animal Preference):
- Microsporum canis: Common in Europe and New Zealand, originating from cats.
- Other species include Microsporum nanum (pigs), Microsporum distortum (a variant of *M. canis*), Trichophyton equinum (horses), and Trichophyton verrucosum (cattle).
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Geophilic Species (Soil Preference):
- Microsporum gypseum: Rarely causes tinea capitis but originates from soil.
