RINGWORM – what is it, how does it spread and how do we treat it?

Ringworm is not caused by a ‘worm’ but is a fungal infection of the superficial layers of skin, hair and nails. It is caused by a specific group of fungi known as the dermatophytes, so ringworm is actuallycalled ‘dermatophytosis ‘. The name ‘ringworm’  probably derives from the lesion caused by the fungi which,in people, is commonly a round raised red ‘ring’ of inflammation.


There are various types of dermatophytes but the most common is probably MicrosporumCanis, which is zoonotic; can be spread between different species and can therefore cause ringworm in cats, dogs and humans.

What are the signs of ringworm in your cat?

Diagnosing ringworm in cats can be a tricky process as the lesions are often very mild or completely undetectable. The fungi feeds on keratin that is found on the outer layers of the skin, hair and nails so these are the areas that we normally see signs such as:

• Scaly patches of skin in the depth on the coat that look ‘ashlike’.
• Hair loss – happens when the fungi attacks the hair shaft causing it to break
• Round,thickened patches of skin
• Patchy hair loss over a greater part of the body
• Flaky broken nails

Lesions are most commonly seen on the head, chest, front legs and along the back. Although ringworm can be itchy in humans, the lesions on your cat usually don’t cause irritation. It is possible for your cat to be a carrier of ringworm and show no external signs itself. These cats can infect their owner or other cats in a multi cat environment.

How does my cat get ringworm?

Ringworm is highly contagious and can be passed from one animal to another by direct contact with the infected animal or by contact with contaminated objects. It is estimated that the fungal spores can ‘hide out’ in bedding, brushes, food bowls, furniture etc for up to 18 months.
It can take around 7 to 14 days sometimes longer, for the fungus to develop into a visible lesion.

Who is at risk?

Contactwith ringworm fungus/ spores does not always mean the animal or person will become infected.Depending on a variety of factors such as:

• The amount of contamination in the environment
• the age of the exposed animal/person
• the general health of he exposed animal/ person

Most healthy animals and adults have no problem fighting off a ringworm infection. However, those with depressed or undeveloped immune systems, such as the elderly, kittens and children, or those with skin sensitivities may be more susceptible to developing ringworm.

How will the Vet diagnose ringworm?

In the ‘good old days’ your vet may have taken your cat into a dark room and shone a ‘Woods lamp’ onto the lesion as MicrosporumCanis lesions often fluoresce under an ultra violet light. Nowadays it is more likely that your vet will take a skin scraping to examine under the microscope or hair samples that can be cultured to grow the fungus in the lab or both. The problem with the latter option is that we now know it can take up to two weeks for spores to develop into fungus. So if your vet suspects your cat has ringworm it will probably be given ringworm treatment in the interim.

Depending on the extent of the lesions it can take between three to five months of treatment to completely eradicate the infection.

So, although ringworm is not life threatening it can be a very tedious, annoying thing to get rid of! Regardless of the extent of an infection and to reduce the potential spread of the fungus into the environment, treatment is always indicated.

How will my vet treat a ringworm infection?

Depending on the extent of the infection your vet will probably use:

• topical ointments/creams or shampoos
•  oral anti-fungal drugs.


• All of the above

Treatment is usually a long haul of at least 6 weeks.  Repeat Skin/ hair samples may be needed for follow up cultures to determine whether your pet is still infected . Depending on the circumstances it may even be necessary to clip your cat or treat other pets in a multi pet household.

It is important to deal with environmental contamination so bedding, bowls, brushes etc should be washed or sprayed with suitable antifungals. This particularly includes your hands and any surfaces the cat has been in contact with.

Will my cat recover from ringworm?

Although as we have shown, treating ringworm is not a quick fix most cats will recover fully. Although, it may recur if treatment was not given effectively, continued for long enough or was not aggressive enough. If your cat has an underlying condition which is compromising its immune system, alternative treatments may be needed.

What about me?

As we have discussed , most healthy adults with a strong immune systems should be able to ward off a possible ringworm infection. However, any break or irritation on the skin will leave it  vulnerable and open to those fungal spores! Good hygiene when you are handling an infected cat is important and if you think you may have a ringworm lesion it is best to seek medical advice and get proper treatment.

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