Ringworm
Dermatophytosis (ringworm) is a superficial fungal infection of the skin, hair, and nails caused by dermatophyte fungi. Despite its name, it is not caused by a worm. The most common species are Microsporum canis (cats, dogs), Trichophyton mentagrophytes (rodents, rabbits), and M. gypseum (soil). It is zoonotic (transmissible to humans).
Symptoms & Signs
- Circular patches of hair loss
- Crusty, scaly skin
- Broken hair shafts
- Mild to no itching (unlike bacterial infections)
- Darkened skin in affected areas
- Brittle, deformed nails
Causes & Risk Factors
Fungal spores from infected animals, contaminated environment, or soil. Cats (especially longhaired breeds and kittens) are common carriers, sometimes without clinical signs. Immunosuppression, young age, stress, and overcrowding increase susceptibility.
Diagnosis
Wood's lamp examination (50% of M. canis fluoresces apple-green). Fungal culture (DTM or Sabouraud's agar) - gold standard. PCR testing for rapid results. Microscopic examination of hair (KOH preparation) showing fungal arthrospores.
Treatment
Topical: miconazole/chlorhexidine shampoo, lime sulfur dips, clotrimazole cream. Systemic: itraconazole or terbinafine for 6-8 weeks minimum. Environmental decontamination essential (spores survive 18+ months). Treat until two consecutive negative cultures.
Prevention
Quarantine and test new animals. Environmental cleaning (dilute bleach). Good ventilation and hygiene. Prompt treatment of affected animals. Reduce overcrowding. Screen cats in multi-cat environments.
Prognosis
Excellent with appropriate treatment. Self-limiting in immunocompetent adults (2-4 months) but treatment prevents spread. Environmental contamination requires thorough decontamination. Zoonotic risk requires owner education.
Affected Breeds (1)
| Breed | Species | Size |
|---|---|---|
| Chinchilla | Small Mammal | Small |