Author: Dr Michelle Gray
It has a misleading name and a bad reputation. Many people have heard of it but far fewer truly understand it. So, what exactly is ringworm? And what else do you need to know about it?
First things first- what is ringworm?
Put simply, ringworm it is a skin infection. More technically known as dermatophytosis, it is not caused by worms, but rather by fungi. Dermatophyte fungi can infect many species, including cats, dogs, and humans. The fungi feed on the keratin containing outer layer of skin cells, hair, or nails.
What does ringworm look like?
The classical red ring lesions which give ringworm (half) of its name are seen mostly in human infections. Dogs tend to get circular areas of fur loss and the exposed skin might look scaley, crusty or inflamed. Ringworm in cats is more variable- it can present as small scabs scattered over the body; as patches of thinning fur on the ears, face, or paws; or as more typical circular lesions.
How do animals get ringworm?
Ringworm is spread via fungal spores. The most common dermatophyte fungi in cats and dogs (Microsporum canis) tends to be spread animal-to-animal, either by direct contact or through shared bedding, brushes, housing etc. There are other dermatophyte species that live in the soil and can cause infection opportunistically if an animal comes into contact with the spores.
Can people get ringworm from their pets?
The short answer is yes. Some of the dermatophyte fungi (including Microsporum canis) are zoonotic- which means they can be transmitted from animals to humans (and vice versa). Human infections are normally self-limiting or readily treatable with anti-fungal creams, unless the person is immunosuppressed. Note there are other dermatophyte fungi that only infect people and are not transmitted from animals. So, it is best to check the fungal species before blaming the pet!
How is ringworm treated?
Treatment of ringworm in cats and dogs involves a combination of oral antifungal medications and topical treatment with either lime-sulfur or antifungal washes. Whole-body topical treatment is particularly important as it reduces spore shedding, the amount of time an animal is infective, and speeds recovery.
How can you stop ringworm spreading?
To reduce the risk of other animals or people catching ringworm it is important to keep infected animals separated; use PPE (e.g. gloves) when handling them; and clean and disinfect any surfaces or objects that they have been in contact with. Removing pet fur daily (using disposable wipes for surfaces, regular machine washing for materials) and cleaning to remove dirt then disinfecting twice weekly (1:10 bleach solutions have good antifungal activity) will minimise the risks of ringworm spreading.
The bottom line- while ringworm is zoonotic, it should not be life-threatening for either animals or humans. Most cases are readily treatable, have an excellent prognosis for recovery, and rarely recur.
Disclaimer: The information and advice in this post is general in nature. It is not intended as a substitute for tailored health care advice from your regular veterinarian.