Short answer: Ringworm is not a worm – it’s a fungal infection (Microsporum canis or Trichophyton species). Dogs get it from contact with infected animals (especially cats and shelter pups), contaminated bedding/brushes, or soil. It’s zoonotic – infected dogs can give it to humans.
What you should actually do
- Microsporum canis is the most common cause – cats are common reservoirs.
- Classic appearance: circular hairless patches, sometimes red/scaly at the edge.
- Diagnosis: Wood’s lamp (50% sensitivity), DTM fungal culture (gold standard), PCR.
- Treatment: topical antifungal (miconazole-chlorhexidine shampoo 2x/week) + oral itraconazole or terbinafine for 4-8 weeks.
- Decontaminate: spores survive 18+ months on surfaces – bleach and HEPA vacuum the environment.
Ringworm is one of the most common skin conditions in shelter dogs and is contagious to humans (especially children and immunocompromised people). Wash hands and supervise child-dog contact until cleared by two negative fungal cultures.
Treatment is typically 4-8 weeks; some cases take longer. The infection can look better while still shedding spores – don’t stop treatment based on appearance alone.
Dig deeper
⚕️ Medical Disclaimer
The information on this page is intended for educational purposes only and does not replace a hands-on veterinary examination. Drug doses depend on your dog’s complete clinical picture, concurrent medications, and the exact product formulation. Always confirm dosing with your veterinarian before administering any medication, and contact a 24-hour veterinary emergency service or animal poison control immediately if you suspect a medication overdose or adverse reaction. Editorial standards: every drug dose published on PuppaDogs is cross-checked against multiple authoritative veterinary references and reviewed by PuppaDogs Veterinary Editorial Team before publication.
