March 3


What it is

Ringworm above the eye
Ringworm above the eye

According to the medical term for ringworm is dermatiphytosis. Because people hear the “worm” in ringworm they sometimes believe there are actual worms in ringworm. This is not true at all. Ringworm is not a worm but rather a fungus. There are numerous types of this fungus found worldwide but most of the fungi that affect dogs are Microsporum gypseum, Trichopyton mentagrophytes, and the most common in dogs is Microsporum canis.

Ringworm is actually a skin disease, a fungal infection located on the skin’s surface. The fungi spores feed on keritan which is a protein found in hair and the top layer of skin. The ringworm fungus seems to thrive best in hot, humid climates. Spores from infected pets can survive up to 18 months after being shed. After exposure, they take a little less than 2 weeks to grow then appear on newly infected animal.

How it’s diagnosed

There are several ways ringworm can be diagnosed. One is by using a special black light called Wood’s lamp. Some species of fungi will glow when exposed but not all of them. It’s been estimated that half of the most common ringworm fungus does not show up with this method. Another diagnostic method is to pluck the hairs from the outside edge of eruption or sore to be examined under a microscope. In this way your vet can determine if the infection is present. The favored and most reliable way for detection or verification is for your vet to scrape scales and crust from the skin of your dog and do a culture. This is a painless procedure.

Some dogs have been known to carry the disease with no outward signs or symptoms, in this case these dogs are still contagious to others. The usual signs are as follows:

  • dandruff flakes
  • redness of skin
  • hair loss
  • raised bumps or nodules on the skin
  • and pets itching
Ringworm above eye... not a good picture
Ringworm above eye… not a good picture


While some pets itch, others don’t seem to. You may also notice small lesions that start as balding areas, they will look dry & scaly; sometimes the ringworm will have the appearance of a pimples. The most popular location ringworm lesions can be found is on the head, but they often show up on ears, paws & limbs of the dog.


How it’s treated

There are two types of treatments, topical and oral. Topical treatments include miconazole cream and Lotrimin cream. Also available are antifungal shampoos and dips. Oral antifugal treatments include griseofulvin or itraconazole or Ketoconazole

Once diagnosed, the usual practice is to administer one round of treatment to the animal. Upon the completion of the first round of treatment the skin of infected animal usually shows improvement. Another fungal culture should be taken after treatment. Even if culture returns negative, treatment is usually continued one month longer. Note: It is important to continue to treat despite appearance appearing to clear up. The pet may still have ringworm and may still be contagious to others as well.


Ringworm can’t be prevented. There has been no reliable vaccine developed. However pet owners can avoid contact with other infected animals and by being aware of likely places and environmental conditions for the disease to transfer. These are locations where numerous animals are housed or pass through such as grooming stations, boarding, vet clinics, pet stores, kennels and shelters etc. Be vigilant. Ask yourself, are these facilities  clean? Are all surfaces & tools cleaned & disinfected between pets?

At home, cleaning your dog’s environment and pet items such as bedding, grooming supplies, toys, dishes, etc. is suggested to prevent reinfection. The ASPCA recommends using 1 part bleach mixed with 10 parts water for disinfecting.

Ringworm is contagious to humans. Species is not a barrier. It is possible for dogs, cats & people to transmit the disease to each other. It also is possible to transfer back and forth between each other if left untreated. You can become infected by having contact either with an infected animal or its environment.

Healthy adult dogs have some resistance, however puppies less than a year old, malnourished or sick dogs are more likely to become infected. The same applies to people, healthy adults can have some resistance as well. Ringworm can be treated easier in humans than animals. Humans are treated by applying a topical medication. Pets may receive both oral and topical medications.



For further reading:

"Ringworm in Dogs." Ringworm in Dogs. Doctors Foster and Smith, n.d. Web. 25 Feb. 2015. <>"Ringworm." ASPCA. N.p., n.d. Web. 25 Feb. 2015. <>"Ringworm in Dogs." Pet Health Network. N.p., n.d. Web. 25 Feb. 2015.


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