Ringworm in Cats: Become an Expert

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Ringworm in Cats

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What is Ringworm in Cats?

Despite the image you have conjured up in your head of a worm-like creature curled up in a ring shape, I have to admit that this is not what ringworm is. Ringworm is a fungal infection that gets its name from causing red ring-shaped irritation marks on the skin surface. So, you were half right, half wrong.

Ringworm, scientifically referred to as dermatophytosis, is a common infectious skin disease in cats that affects the skin, hair and nail areas. While there are many species of dermatophytes, the scientific name for skin-infecting fungus, it is the Microsporum canis species that is responsible for all ringworm infections in cats.

While you might already be tired of all these scientific terms, we have one more to introduce to you, and this one is important because it infects, I mean includes, you. The species of fungus mentioned above, Microsporum canis, is zoonotic. What this means is that if your cat is infected with ringworm, then there is a high chance that YOU, and your other cats, can be infected by them.

To find out more about how ringworm in cats is picked up and transmitted continue reading below.

How do Cats Become Infected with Ringworm?

Cats are infected with ringworm in four main ways:

  1. Contact with an animal that is already infected (e.g., another cat or dog – or even the prey they caught during a hunting session)
  2. Contact with an object that has traces of the fungus on it
  3. Exposure to the fungus in a contaminated environment (e.g., a woodland area)
  4. The fungus may also be airborne (e.g., carried by air or dust particles)

After any of these have occurred, the fungal spores are in direct with the cats’ fur coat. From here, it can go one of two ways:

  1. The cats’ natural defence mechanism take care of the spores (e.g., self-grooming and immune system)
  2. The spores surpass the cats’ natural defence mechanism and invade the cells and begin germinating (infecting)

All ages, sexes and breeds of cats can fall victim to ringworm. However, kittens and older cats can be more susceptible to such an infection.

However, there are three categories of cats who are more susceptible than others. These are:

  1. Kittens
  2. Older cats
  3. Longhaired cats

First, kittens are more vulnerable to ringworm because they have a lot of skin exposed and are less versed in self-grooming. Second, older cats have a weaker immune system which means that their natural defence mechanisms are weaker at fending off infections. As well as this, older cats are less flexible and are therefore not able to properly self-groom. Lastly, longhaired cats have more distance between the tips of their hair follicles and their skin. This means that their grooming attempts will often not reach their skin, allowing the fungus to cultivate.

The transmission of ringworm in cats can also be very deceiving. Cats may appear to be healthy and uninfected even though they are carrying around the fungus. Even cats with immunity to ringworm can transmit the disease to other cats or humans.

Read below to learn how to tell if your cat has ringworm.

What are the Symptoms of Ringworm in Cats?

Besides the obvious signs of ringworm that are patches of hair loss and red, irritated areas that have become crusty, there are many more symptoms that can show signs of ringworm in cats. See the list below:

  • Itchiness – the severity of itchiness depends on the condition of ringworm that your cat has been infected with
  • Irritated skin – red patches of skin that look sore or infected
  • Hair loss – when the skin becomes infected, there will be a loss of hair in that area
  • Darkening of skin – similar to irritated skin, but you may find that your cat has dark areas of skin (hyperpigmentation), although this is most common post-infection
  • Nail infection – some cases of ringworm develop only around the nails
  • Overgrooming – in line with irritation, your cat may overgroom themselves from distress

How is Ringworm in Cats Diagnosed?

Some veterinary experts might be able to diagnose ringworm in cats purely off of visible symptoms. However, to be sure, some clinical tests can be run to obtain more concrete results. There are five possible diagnostic tests:

  1. Wood’s Lamp

Wood’s lamp is a jargon term for shining a fluorescent light on an infected area of skin. Under the fluorescent light, vets will be able to observe the presence of the fungal spores. This is because when the spores grow, they secrete a chemical onto the surrounding hairs. This chemical glows under the fluorescent light. If the chemical is present, then it means they are a step closer to diagnosing your cat with ringworm.

However, it should be mentioned that Wood’s Lamp method is not the most accurate or successful. Many other chemicals can also glow under the fluorescent light, such as skin ointments. Also, some strains of fungus do not glow under fluorescent light. In this case, we look to other diagnostic methods.

  1. Microscopic Examination

This method takes samples of hairs and skin from the infected area and examines them under microscopic equipment. The results from this method can be very accurate. However, this is a long process as the samples need to be sent off for expert consultation from professional scientists at a laboratory. 

  1. Fungal Culture

Fungal culture diagnosis is when samples of hair and skin from the infected area are taken and then cultivated in a medium that is optimal for fungal growth. This method seeks to see if there is fungus on the samples taken and whether the fungus will grow (cultivate). If the fungus grows, then we learn that it is also present on the cat. The main downside to this diagnostic method is that it can take weeks to see the fungus cultivate. Also, as with the microscopic examination, it has to be sent off to a laboratory.

  1. Biopsy

This method is the most invasive method of them all, and will probably not be recommended in most cases. To go forth with this method means that a piece of your cats’ skin will be cut off and sent to a laboratory for close examination. Despite it being invasive and slightly painful, this diagnostic method reveals incredibly accurate results.

  1. PCR

PCR stands for polymer chain reaction. This method is very scientific. Without getting into it too much, it is similar to the culture test but uses newer technology. The results from this diagnostic method are very accurate, and it doesn’t take long either.

Overall, there is a diagnostic method for all severities of ringworm in cats. Again, as with all cat illnesses, always seek expert medical advice. They are there to help you and your kitty-cat maintain optimal health.

How is Ringworm in Cats Treated?

There are two main medical treatments for ringworm in cats. They are often used together to combat the infection to its fullest potential. These are:

  1. Topical Treatment

Your local veterinary expert will be able to recommend you a variety of creams or ointments that you can apply to the affected area of your cats’ skin. Application of these medications will often follow a program that lasts several weeks to several months.

For longhaired cats, it will be recommended that the hair on and around the infected area is shaved off or clipped back during the process of treatment. Medical shampoo may also be prescribed as a treatment – this will require some patience.

  1. Oral Treatment

Oral anti-fungal drugs will also be recommended by your local veterinary expert. These will also follow a program that lasts several weeks.


  • To make sure you don’t contract the infection, or spread it around your house, make sure you wear protective equipment when applying creams/ointments and oral medication. Also, make sure to sterilise all surfaces used in the process of applying such treatment.
  • Some of the diagnostic methods, such as fungal culture, will be undertaken again, or for the first time, after a couple weeks of treatment has passed. This is to make sure that the prescribed treatments are working effectively.
  • If you have multiple cats, make sure that the infected cat is separated from the others that are, hopefully, not also infected.

Am I at Risk if My Cat has Ringworm?

The short answer: Yes.

Listed below are some of the decontamination processes you should do to minimise the spread of ringworm:

  • Throw out all cat-lounging equipment (rugs, blankets, brushes, toys)
  • Ideally, purchase a new hoover (cheap) that can be used to clean all carpets and furniture thoroughly (remember to clean the hoover afterwards)
  • Scrub all surfaces (with strong detergent) in your house that the cat has frequent contact with, and all the other surfaces too, just to be safe.
  • Consider a portable dehumidifier – this is because fungal spores can cultivate in humid environments

While you may be exhausted after the first deep clean of your house, make sure you keep on top of daily cleaning (hoovering, disinfecting surfaces etc.) to avoid dealing with ringworm in cats in the future.

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