What are Dermatophytes?

About Dermatophytes:

• They are a group of fungi that live off keratin, a substance in hair, nails and the outer layer of the skin.
• They don’t infect living tissue.
• They can cause skin lesions in humans and animals.
• Infections caused by dermatophytes are called dermatophytosis.
• The fungi use keratin as a carbon source and colonise keratinised tissue, such as hair, skin or nails.
• Major genera of dermatophytes include Trichophyton, Microsporum and Epidermophyton.
• Dermatophytes are highly contagious.
  • Some dermatophytes are spread directly from one person to another (anthropophilic organisms).
  • Others live in and are transmitted to humans from soil (geophilic organisms), and still others spread to humans from animal hosts (zoophilic organisms).
  • Transmission of dermatophytes also can occur indirectly from fomites (e.g., upholstery, hairbrushes, hats).
• Anthropophilic organisms are responsible for most fungal skin infections.
• Why do dermatophytes cause so many different types of disease?
  • All dermatophytes infect host surfaces containing keratin, including skin, hair, and nails.
  • As such, the same infecting organism could cause disease in the foot, fingernail, body, or head.
  • Both climate and lifestyle contribute to the prevalence of dermatophyte infections.
  • Tropical climates and overcrowding predispose populations to dermatophyte infections.
  • Increased urbanization, including the use of occlusive footwear, community showers, and participation in sports, has been linked to higher prevalence of Tinea pedis and onychomycosis (nail infections).
  • It is very rare for a dermatophyte to cause an invasive or disseminated infection, although cases in immunocompromised patients have been reported.
  • Disease severity correlates with the ecological niche of the infecting dermatophyte.