Ringworm in dogs and cats

photo of dog and a cat on white background


Despite its name, ringworm is not a worm; it’s a fungal infection of the skin. It’s also known as ‘dermatophytosis’.

Ringworm can infect many different species including dogs, cats and humans. It’s very contagious and spreads easily.

It can take a few weeks to cure ringworm but if your pet is otherwise fit and healthy, the outlook is good with treatment from your vet.

Symptoms of ringworm

  • Hair loss or patchy fur (alopecia)
  • Dandruff
  • Patches raised, red skin (often circular but not always)
  • Inflamed, infected, crusty skin
  • Mildly itchy skin.

When to contact your vet

Contact your vet for an appointment if your pet has any of the signs above or you think they may have ringworm.

You know your pet best. If they don’t have the symptoms listed above but you are still concerned it’s always best to contact your vet.


Ringworm is caused by a fungus that invades the skin and hair. It spreads easily by touching or getting close to infected skin. It also survives in the environment for a long time so can spread to others this way.

Vulnerable pets (such as the old, young and poorly) are most at risk of catching ringworm.


Your vet may use a special lamp to look for ringworm or take some hair and skin samples.

Treatment may include:

Medicated shampoo

  • Your vet may prescribe a special anti-fungal shampoo to help to kill the ringworm. This can take several weeks to work.

Coat clipping

  • Your pet’s fur may need to be clipped to stop ringworm spreading to easily and also to make sure any skin treatments work properly.

Prevent spread and re-infection

  • It is important to stop ringworm spreading; it’s very contagious to other pets and people in the house.
  • Cats are particularly contagious.
  • Take sensible precautions such as:
    • Vacuuming the carpets, sofas and curtains regularly.
    • If possible, keep your infected pet away from other pets in the house.
    • Until their infection has cleared up, make sure you wear disposable gloves when handling and treating your pet. Wash your skin and clothes after handling them.


Treatment for fungal skin disease can be expensive and it’s not something you can predict. Consider insuring your pet as soon as you get them, before any signs of illness start. This will ensure you have all the support you need to care for them.

It’s also very important to speak openly to your vet about your finances, the cost of treatment, as well as what you think is right for your pet. There are often several treatment options so if one doesn’t work for you and your pet then the vet may be able to offer another.


It can take a few weeks to cure ringworm but treatment is effective in most cases. You will need to keep an eye out for any other pets or people in the household developing ringworm.


Preventing ringworm isn’t possible because it’s not visible to the naked eye. Fortunately, it’s not a very common skin condition.

Contact your doctor if you think you may have developed ringworm.

Published: January 2019

PetWise Pet Health Hub – brought to you thanks to support from players of People’s Postcode Lottery 

Written by vets and vet nurses. This advice is for UK pets only.

Illustrations by Samantha Elmhurst