Ringworm in Cats - What is Ringworm?
Contrary to its name Ringworm is not a worm at all but a fungus called Dermatophytes. Dermaphtytes means 'plants that live on the skin'. In the past, because of the circular lesions made by the fungi they were thought to be caused by worms, hence the name ringworm.
The fungi live on the surface of the skin and in the skin follicles feeding on dead skin tissue and hair.
There are three different types of fungus that can cause ringworm but the most predominant ones found on cats and dogs is Microsporum canis.
What does Ringworm look like on my cat or dog?
The usual symptom is a round hairless lesion. The characteristic "ring" that we see on humans doesn't always appear as a ring on cats. This lesion will grow in size and often become irregular in shape.
The fungi cause the hair shafts to break off and this results in patches of hair loss. Ringworm are commonly found on the face, ears, tail and paws. The lesions are scaly and may or may not be itchy and often the skin is reddened and inflamed.
How does my cat or dog catch ringworm?
Transmission can happen by direct contact with another infected animal or person. It can be passed from cats to dogs and visa versa and from pets to humans and from humans to pets.
The fungal spores can live in the environment for a long time and can be found in carpets, bedding, grooming equipment etc and can infect your cat when it comes into contact with them.
The incubation period is 10-12 days. This means that following exposure to the fungus, about 10-12 days will pass before any lesions occur.
In rare cases ringworm can be spread by contact with infected soil. The fungus can live for months in soil if the nutrients are right.
Fortunately the spores are easily killed with a solution of bleach and water. 500mls of bleach to 4 liters of water.
Can Humans catch Ringworm from Cats or Dogs?
You can contract ringworm by touching an animal with ringworm. Ringworm can spread while petting or grooming cats or dogs. You can also get ringworm from cows, goats, pigs and horses.
Are all cats or dogs susceptible to ringworm?
Healthy adult cats or dogs usually have a resistance to ringworm. Young cats and kittens and puppies are more susceptible because their immune system hasn't fully developed. Many cats and dogs are carriers of ringworm but show no symptoms. They can, however, infect other animals or humans.
Diagnosis of Ringworm
To diagnose Ringworm your vet will need to do one of the following tests. It is not possible by just looking at the skin to make the diagnosis.
An ultra violet lamp also known as a black light. Your vet may use this as 50% of microsporum canis will glow under the lamp.
Your vet may look at part of the hair or skin from the lesion under a microscope.
Your vet may decide to take a scraping from the lesion and send it away to the laboratory to see what the culture grows.
Is there a cure for Ringworm?
If no treatment is carried out, ringworm will run it's course in two to four months and the symptoms will resolve themselves. However, treatment is recommended to save your cat or dog from suffering any longer than necessary and to cut down the period of time they are contagious
Your vet may prescribe Griseofulvin for your cat or dog. It is an anti fungal drug that is used for pets with ringworm but it does have some side effects so be sure to consult your vet before giving any medication. Griseofulvin inhibits fungal reproduction.
Shampoos and Dips:
Lime sulfur dips are often recommended by your vet.
Dips should be given twice a week and can be performed either by your vet or at home. Please be aware that Lime Sulfur will stain clothing and jewelry and will cause temporary yellowing of the cat or dog's hair. It also smells very strongly of rotten eggs. Follow your vets instructions for mixing the dip.
Decontaminate the environment
Use bleach mixed at 1:10 on any surface that you can. It will kill 80% of the spores. Vacuum on a daily basis a dispose of vacuum bags which will contain the spores. Steam cleaning of carpets and furnishings will also kill a large number of the spores.
Don't forget your cat or dog's bedding or basket. Wash the basket down with a bleach solution and wash the bedding in very hot water. Confine your cat or dog to one room of the house to avoid spreading spores all over the house.