veterinarians

Ringworm: It's Not What You Think!

Based on an article that first appeared at

Despite its name, many pet parents are surprised to find that ringworm isn’t a worm—instead, it is a skin disease caused by a fungus. Because the lesions of this skin disease are often circular, it was once thought to be caused by a worm curling up in the tissue, but this disease actually has nothing to do with worms at all!

Ringworm, also known as dermatophytosis, is an infection in the superficial layer of the skin, hair and nails. The fungi that cause ringworm live in hair follicles and cause the hair shafts to break off at the skin line, resulting in round patches of hair loss. As the fungus multiplies, the lesions may become irregularly shaped and spread over the pet’s body.

Other symptoms of ringworm may include:

  • Poor hair coat
  • Dandruff
  • Reddened skin
  • Itchiness

It is important to note that many other skin diseases have these same symptoms. In many cases, a pet examined for ringworm will actually be diagnosed with pyoderma, or a bacterial infection of the skin.

Though it is not common, ringworm is especially important to treat because it may be transmitted to dogs, cats and humans and vice versa. If your child has ringworm, he/she may have acquired it from your pet or from another child. Adult humans are usually resistant to infection unless there is a break in the skin, but children are quite susceptible. If you or any members of your family have suspicious skin lesions, please see a physician.

A veterinarian can diagnose ringworm using various methods, including identifying the lesions on the skin, examination of the hair under a microscope, fluorescence of infected hairs under ultraviolet light or culturing the hair. Treatment depends on the severity of the infection, how many pets are involved, if there are children in the household and how difficult it will be to disinfect your pet’s environment.