Ringworm in Dogs: Fungal Infections in Dogs

Ringworm in dogs is caused by the fungi Microsporum and Trichophyton. It is the primary fungal infection that troubles dogs. Such fungi live in dead skin tissues, nails, and hairs – particularly, but not exclusively, among young dogs. The ringworm fungus is most prevalent in hot, humid climates, but interestingly enough, most cases of ringworm occur in the fall and winter.

Ringworm infections can come through contact with a contaminated object  or another infected animal. Spores can be transmitted on grooming equipment like clippers or brushes or from unsterilized boarding cages. Most healthy adult dogs are resistant to this fungal infection. It is usually puppies or dogs with suppressed immune systems that pick up ringworm.

Symptoms of Ringworm

Ringworm can usually be identified by a small hairless patch that reveals a round, dry and scaly lesion. The lesion may have small pustules. Usually these lesions present on the head but can also be found on the tail, feet and legs. .

Diagnosis of Ringworm

Ringworm fungus will glow when put under a Wood’s Lamp that uses ultraviolet light. This is effective for identifying roughly half the species of ringworm and an inactive infection will not fluoresce. The next step for diagnosing ringworm is to make a culture from the scales of the lesions. This is a very routine culture with culture mediums that are specific to ringworm identification.

Treatment of Ringworm

Treatment  begins by shaving around the affected areas. Fungicidal shampoo and topical medications are typically used and possibly dips in a lime sulphur solution. Anti-fungal medication is applied twice daily. Effective meds include Lotrimin cream, miconazole cream or 1% chlorhexidine ointment.

Oral anti-fungal medications may be prescribed. itraconazole, ketoconazole or griseofulvin, and itraconazole may be used for several months.

Caution: ringworm can be transmitted to people

Ringworm is very contagious. Dogs with ringworm should be isolated from other pets and must be kept away from children until the infection is gone. This can be 3 months or more. Hand-washing is important whenever handling infected dogs and you may consider wearing disposable gloves. Adults should wash their hands well after handling a dog with ringworm.

Related articles include:

Moldy Dogs: Fungal and Yeast Infections in Dogs

Fungal Infections in Dogs: Aspergillosis

Fungal Infections in Dogs: Blastomycosis

Fungal Infections in Dogs: Histoplasmosis

Fungal Infections in Dogs: Cryptococcosis

Fungal Infections in Dogs: Pythiosis

Fungal Infections in Dogs: Coccidioides immitis/Valley Fever

Fungal Infections in Dogs: Sporotrichosis

Fungal Infections in Dogs: Zygomycosis

Your Pet May Have a Mold Allergy


  1. patricia whitman says

    I have Addison’s also dogs can get it, could
    i have gotten it from black mold found in ceiling tiles…I lived in such a house for over 10 years. thank you