What You Need To Know About Ringworm

Posted on
June 12, 2018

“Ringworm”: do you picture a twitching white worm curving inwards in the shape of a ring? Or maybe you connote this word with “tapeworm” or “roundworm” at first. Ringworm, roundworm—same thing? Though if you know what a dermatophyte is, then maybe you’re too smart for that. Ringworm is not a worm at all, but a pathogenic fungus that infects almost all species of domestic animals. They are zoonotic, meaning they can be transmitted from animals to humans and vice versa. Disturbed yet?

Calm down a bit—the more you know, the more you can do. Read on to learn about: 

  • The basics: species, symptoms, and sources
  • How to treat ringworm
  • How to clean up environmental contaminants
  • Prevention

The Basics

What is it exactly?

It wasn’t until the mid 19th century and into the the early 20th that scientists finally began realizing that the red sores and bald spots on the skin resulted from a fungus, not a worm as the ancient Greeks and Romans had led us to believe. Hence, why there is no such thing as “ringworms” (check the dictionary if you don’t believe me...I already did).

Ringworm does not live inside the body like roundworms or tapeworms, but on the hair follicles. It survives by eating keratin, the main protein that gives the hair its structure. It can technically live in the nails, too, since they also contain keratin, but this is less common. There are three main species of ringworm, but Microsporum canis is the most common by far, responsible for 94 percent of ringworm in cats and 65 percent in dogs. In general, ringworm is more common amongst our feline pets. In horses and cats, Trichophyton mentagrophytes is also common, and Microsporum gypseum, not so much.

microscopic view of Microsporum canis ringworm
A microscopic view of Microsporum canis. Photo courtesy of the University of Adelaide.


The circular or semicircular bald spots, sores, or lesions are good indicators of a ringworm infection in your pet. They can pretty much show up on any area of your pet’s body, but depending on how much the condition has progressed, the spots will be widespread or more localized. In horses, ringworm is especially common at the saddle and girth areas since the skin comes into contact with the tack or harness in these spots. Overall, the most basic, tell-tale signs are a lack of hair in the suspected spot and inflammation—the immune system’s natural reaction to invaders.  

Though recognizing ringworm might seem simple, a skin lesion could be something other than ringworm, so having a veterinarian look at your pet is the best option. A vet will evaluate the condition by examining your pet’s hair under a fluorescent lamp, a microscope, or with a fungal culture, and if the results are positive, they can subsequently prescribe an oral medication.

horse itching & biting under front leg
If your horse’s skin is flaky or red, especially near the saddle or girth areas, it could be ringworm.


Your pet needs to have direct contact with ringworm or ringworm spores in order to pick it up, so contact with an infected animal or human or with environmental contaminants can spread the fungi. Fungal spores can live on a multitude of items—carpets, brushes, furniture, curtains, bowls, bedding, towels, etc.,—for up to 18 months. In the case of horses, dormant spores can live in the woodwork of a barn or fencing. On top of this, the time at which your pet is exposed to ringworm and the point at which symptoms begin to show can range from seven to 21 days. The take-home message, then, is that even if you don’t know of a recent case of ringworm, your pet could still have it.

Sometimes, a human or animal can act as an asymptomatic carrier, meaning that they can spread ringworm to others without displaying symptoms themselves. Finally, Microsporum gypseum, the least likely ringworm species, live in the soil. Even though direct contact is necessary to contract ringworm, it does not always result in an infection, and in animals or humans with weakened immune systems, infection is more likely.

cat laying on a rug
Unfortunately, ringworm can make a temporary home out of many places, including the rug.

How to Treat Ringworm

Treatment for ringworm is not complicated: topical and oral treatment are often used in conjunction. Topical treatments in particular help prevent environmental contamination of ringworm by directly targeting the fungi. Fauna Care Anti-Fungal Spray uses the key ingredient ketoconazole, which works by interfering with the growth of the fungal cell walls so that the fungi leak and die. In the form of a spray bottle, Fauna Care Anti-Fungal Spray eliminates the need for owners to apply an ointment or cream treatment—other common topical options—onto their pet, thus contaminating their own skin. When applying topical treatments, it can be helpful to trim or shave long hair near the infection so that treatment reaches the fungus at the skin’s level.

girl holding cat & rubbing its chin
You might have to apply a topical treatment directly, but not like this! Use some gloves.

Veterinarians must prescribe oral medication, and common options are griseofulvin, itraconazole, and terbinafine. Most treatments—topical and oral—need to be used for at least six weeks, even when symptoms seemingly subside. A vet will confirm that your pet is ringworm free, often with another fungal culture, several weeks after treatment commenced.   

Eliminating Environmental Contaminants

The hard part of getting rid of ringworm—and preventing a new round of infection in the future—is cleaning up its traces in your home. Since ringworm is microscopic, you really have to clean everything to ensure that your home is rid of it. Fungi and fungal spores lurking in your home will only result in an ongoing ringworm cycle, and since you usually don’t become immune to ringworm, this would be incredibly unfortunate—for you and your pets. Here are some tips to clean up the house:

  • Use a solution of bleach and water to disinfect surfaces your dog has been in contact with; a 1:10 ratio is adequate . A commercial cleaner with a fungicide can also be used.
  • Vacuum carpets and discard the vacuum bag daily. Vacuuming is important since the fungi can live in the hair follicles shed by your pet.
  • Wash clothing and linens with hot water and use a hot dryer.
  • Keep rooms well ventilated by opening up windows.
a vacuum cleaning the carpet
The key to clearing up ringworm: lots of cleaning.

It is important to isolate infected pets—maybe by keeping them in one room with few belongings in it for easy clean-up. This is especially important since infected pets remain contagious for about three weeks after treatment has begun.

Emphasizing Prevention

Since ringworm is more likely when the skin is vulnerable due to wounds, you should address your pet’s cuts, wounds, and burns as soon as possible in order to prevent a further complication such as fungal infections. Fauna Care Sprays for cuts—First Aid, Silver, and Zinc Spray—are helpful in combating wounds. Fauna Care Protect & Condition Spray can also help to ensure that your pet’s skin is protected and hydrated in order to fend off pathogenic fungi. Here’s a comparison: Staphylococci bacteria live on human skin, but the (healthy) skin’s role to act as an antimicrobial barrier prevents us from contracting a staph infection.  The same is true when your pet comes into contact with pathogens.

Questions? Interested in being featured on this blog? Click here to get in touch!
Posted on
June 12, 2018