Definition of Ringworm

“Ringworm” disease has nothing to do with worms. It is the common name for a fungal infection of the superficial layers of the skin, nails and hair fibers. Also called dermatophytosis, ringworm is highly contagious among animals and can infect humans as well.

Causes of Canine Ringworm

Ringworm is caused by fungal microorganisms, not by worms. The most common species of ringworm fungi in domestic dogs and cats are Microsporum canis, Microsporum gypseum and/or Trichopyton mentagrophytes. All of these fungi thrive in non-living keratinized tissues – outer skin layers, hair follicles and nails. Microsporum gypseum also lives in soil and is more common in the summer and fall. Ringworm is spread by direct physical contact and is extremely contagious. Ringworm infections are more prevalent in hot, humid climates.

Prevention of Ringworm Infection

The best way to prevent dermatophytosis, or ringworm, is to prevent contact between affected and unaffected animals.

Special Notes

While ringworm often resolves on its own (is “self-limiting”), prompt treatment can prevent the spread of infection to other pets, and to people. Veterinary personnel and owners should be cautious when handling dogs with ringworm and preferably should wear gloves when applying topical medication.