No, worms don’t wear jewelry, nor does ringworm result in disgusting squirmy deposits in the litter box or on the lawn. This fungal infection grows on keratin, the substance that makes up the hair shaft, and causes skin disease.

Ringworm easily spreads to humans, too, and very young children, older folks, or those with a depressed immune system are most susceptible. In people, ringworm infections spread outward from a central spot. As the inside central sore heals, the “ring” of reddened skin surrounding the area gives it a characteristic look and name.

Pets won’t necessarily show this distinct pattern, though. Sores expand but not in rings, and can look like other skin diseases. Infected hairs break off, and leave a stubby patchwork fur pattern, and mild to severe crusty sores also can develop. Some pets become itchy, others do not.

There are different kinds of ringworm. Microsporum canis most commonly affects pets, especially cats. Another type of ringworm, carried by rodents, may infect dogs that dig through rodent burrows. A third kind of ringworm lives in the soil.

Healthy adult cats and dogs often resist infection because their immune system squelches any exposure. But very young pets, old ones, and those with inadequate immunity are at greatest risk. During kitten season, chances are you may encounter ringworm in a new furry baby.

Some healthy pets become “typhoid Mary” carriers, with no problem themselves, but spread infection to other animals. Once a pet becomes infected, spores contaminate the environment and can remain infective for months. Even if only one pet has ringworm, you must treat ALL pets.

Your veterinarian may diagnose ringworm first by shining a specialized Wood’s Lamp on the pet to see if any infected areas glow lime green. A culture confirms infection. Suspect hairs are collected and placed in a special medium that encourages fungus to grow, so it can be identified under the microscope. Treatment consists of a three-prong approach, including oral medication, topical treatment, and dealing with the environment.

The most common drugs include ketoconazole (for dogs only!) and itraconazole (Sporanex) for cats. Lime sulfur dips are the only topical proven to be effective, and usually require two dips per week.
Longhaired critters must be clipped first to reduce the amount of contaminated hair. Clipper blades or scissors must be disinfected afterwards to avoid spreading infection with the next use. Shampooing or scrubbing the pet can make the infection worse by breaking off infected hairs and spreading the spores over the body.

The spores are nearly indestructible so it’s hard to treat the environment. Only concentrated bleach, cancer-causing chemicals, and enilconazole (toxic to cats) effectively kill ringworm spores, and none of those options work well in your home.

• Get rid of spore reservoirs such as carpet, drapes, pet bedding, and the like.
• Repeatedly bleach all surfaces with a 1:10 bleach and water solution.
• High temperature steam also may be effective.
• Vacuum repeatedly, but remember to toss out the bag every time, or you’ll simply spread the spores. Disinfect the vacuum, too, with the bleach and water spray.
• Sunlight also kills ringworm spores. Anything that can’t be thrown away or bleached can be left outside in the bright sun for a couple of weeks.

You must treat the pet and continue disinfecting the environment until follow up cultures of the pet are negative. In a single pet home, treatment may be needed three to eight weeks, but probably will be longer in multipet households.

But it’s worth it--just ask your bald, scabby pet.

Think your pet may have Ringworm? Check out the Pet Vet Disease and Condition Finder to find out