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Black and white cat scratching

How External Parasites Affect Your Cat's Skin

Dermatitis in cats refers to when their skin becomes red, sore and sometimes swollen or blistered. Dermatitis may arise as a result of an external factor that causes inflammation, such as external parasites, and this can lead to an allergic reaction.

External parasites found in your cat's natural environment, both indoors and outdoors, can irritate their skin and potentially result in an allergic reaction.

Your cat's skin needs to be looked after with care as dermatitis caused by parasites can weaken your cat's natural skin barrier and make them more susceptible to secondary infections.


grey cat sat in cat bed

Where Do External Parasites on Cats Come From?

Your cat can pick up external parasites, such as mites, fleas, ticks and lice from contaminated sources, both indoor and outdoor. If your cat comes into contact with an infected animal or contaminated objects, such as blankets, sofas, carpets or soft toys, they may be more likely to pick up the parasite and show common signs.

illustration of cat by window

What Are the Common Signs of an External Parasite in Cats?

Two common causes of parasitic dermatitis include flea bites and mange (mites).

Look out for some of these common signs that may indicate a parasite has infested your cat:

  • Hair loss
  • Redness
  • Itching
  • Scratching
  • Licking and chewing their skin
  • Discoloration (if licking has occurred)
  • Crusts or scabs
  • Odor
  • Illustration of cat with vet

    Seek advice from your veterinarian

    At first instance it may be unclear what type of parasitic infection or allergic reaction your cat is suffering from, however, your veterinarian will be able to assess and diagnose your cat to identify why such a reaction is occurring. 

    What Is Mange?

    Mange refers to skin diseases caused by mites and can be differentiated into the following types; Notoedric Mange, Demodectic Mange and Sarcoptic Mange.

    illustration of parasite on cat

    Notoedric Mange

    Signs of Notoedric Manage commonly begin around the ear area, before spreading to the face and potentially the body if action is not taken against the infection. Notoedric mange is spread through direct contact, however is a rare condition in the US with only regional hot spots of infection.

    illustration of cat passing parasite to another cat

    Demodectic Mange & Sarcoptic Mange

    There are two types of demodectic mange in cats. The first type results from mites that are present in all cats but only become an issue when the immune system is compromised. The second type of Demodectic Mange can be highly contagious and arises from mites that live in the skin.

    Also known as 'scabies', Sarcoptic Mange in cats can result in uncomfortable sores, hair loss, and excessive itching. Sarcoptic Mange is also very contagious in cats.

    What Is the Difference Between Fleas, Lice and Ticks?


    Illustration of flea


    Fleas are tiny insects with the ability to attach themselves to animals to feed. Fleas can lead to excessive itching and scratching in cats in an attempt to relieve some irritation. In some instances, cats can also suffer from allergic reactions to fleas, referred to as flea allergy dermatitis.

    Illustration of a lice


    Lice are tiny organisms that can be found in your cat's hair and attached to their skin. Lice on cats can lead to scratching more than usual and hair loss if not found and managed quickly.

    Illustration of tick


    Similar to fleas, ticks also feed off the blood of animals. Check your cat regularly for ticks and remove them carefully following the proper advice from your veterinarian. If ticks aren't removed quickly and correctly they could lead to serious illnesses.

    Illustration of owner taking pet to vet

    How Might Veterinarians Manage Parasites?

    Once your veterinarian has identified the type of parasite that has attached itself to your cat, they will be able to recommend appropriate management options.

    Fleas - If your cat is suffering from fleas, a veterinarian may recommend a cat-safe flea control product to first remove the existing parasites from their coat. You will likely also need to treat your home to remove existing parasites and stop the reproduction of future fleas.

    Mange - If diagnosed with mange your veterinarian will recommend the appropriate management to remove mange from your cat's skin. They will likely also suggest different methods to health and strengthen their skin. 

    For advice specific to your cat's needs make sure you speak to a veterinarian who will be able to provide a detailed plan of action to support them.

    Understand How Parasitic Allergies Can Affect Your Cat

    Increase your knowledge of how parasites can cause allergies for your cat with these short frequently asked questions.

    Yes, fleas can jump from cats to humans and bite, however, fleas cannot survive for long periods of time on human hosts.

    Your veterinarian will be able to recommend appropriate management options based on your cat's individual requirements. In some instances, they may recommend a cat-safe flea control product. 

    Yes, sarcoptic mange can be passed onto humans as well as other pets, although the mites may not be able to complete their usual lifespan on a human. Despite this, the mites may still cause some level of discomfort for humans.

    There are three types of mange that can occur in cats: Notoderic, Demodectic and Sarcoptic. Speak to your veterinarian if you believe your cat has mange and they will be able to advise which type they are suffering from and the best management options.

    If your cat has mange they will likely be itching and scratching more than usual. Hair loss, redness and discoloration of the skin can also indicate an external parasite is present.