Understanding itchy skin in cats and dogs

Itchy skin is a common problem among cats and dogs. It can be distressing and frustrating for both pets and their owners and can lead to self-trauma, secondary infections and other complications. Identifying the underlying cause is important for effective treatment and management. Some common causes of itchy skin in cats and dogs include:


An allergy is a state of hypersensitivity when exposure to a harmless substance (an allergen) causes the body’s immune system to overreact. It is common for allergies in pets to present as skin problems rather than respiratory problems as in people. Signs of an allergy can vary considerably but most often manifests as itching/scratching, chewing and/or licking excessively which can also sometimes coincide with recurring skin/ear infections and hair loss. Allergies are one of the primary causes of itchy skin in pets and can be triggered by various allergens. Year-round environmental allergies can be indistinguishable from food allergies, so it can take a lot of unravelling to determine the exact cause. It’s important to know that allergies cannot be cured, only managed, which often involves medication to relieve symptoms such as itch, inflammation and discomfort associated with the allergy or to treat secondary bacterial or fungal infections.

Allergic skin disease can be broken down into four categories: flea allergy, food allergy, environmental allergy, and contact allergy.

  • Flea Allergies are the most common skin disease in cats and dogs causing severe itching and skin inflammation. It requires 100% flea control for your pet to remain symptom-free. 95% of fleas live in the environment so strict flea control often involves treating your pet as well as your home. Animals are allergic to flea saliva so the bite of just one flea is enough to set them off itching for the next few weeks!
  • Environmental Allergies (atopy) is a predisposition to develop skin problems from exposure to a variety of common allergens such as plants, pollen, dust mites and mould spores. It can be difficult to determine which allergens are causing the problem so our options are to manage the symptoms without knowing the exact cause, or to identify the allergen through blood tests or intradermal skin testing and then treat with desensitisation. The latter can seem costly but when compared to multiple vet visits for allergy flare-ups, it may not be that much different in the long run.
  • Contact Allergies are a group of allergies that cause delayed itching following direct contact with the offending substance. The most common contact allergy in NZ is to Wandering Jew, a ground cover plant found on riverbanks and in the bush.



The presence of external parasites such as fleas, ticks, and mites can cause intense itching in cats and dogs. Persistence with the correct treatment and medication will often completely resolve the skin issues if parasites where the sole cause.

Secondary Skin Infections

Secondary bacterial or fungal infections can develop in conjunction with itchy skin. These infections often occur due to persistent scratching, licking and/or chewing, creating a desirable environment on the skins surface for bacteria and yeast to thrive. The infection occurs secondary to the underlying problem, such as an allergy, which caused the initial itching in the first place.

Nutritional Deficiencies

Poor diet or nutritional imbalances can affect the health of a pet’s skin and coat, making them more susceptible to itching. Essential fatty acid deficiencies, in particular, can contribute to dry, flaky skin and itching.

Underlying Disease

Itchy skin can sometimes be a symptom of an underlying disease. Some conditions, such as hypothyroidism or Cushing’s disease, can disrupt the normal functioning of the skin and coat, resulting in itching and hair loss. Potential underlying disease will require thorough investigation, evaluation and treatment from a Veterinarian.


  • Maintain a healthy diet with high-quality nutrition.
  • Strict flea and external parasite control. Even if your pet isn’t allergic, fleas and external parasites can make their skin condition worse.
  • Keep your pet’s environment clean and free of allergens. Wash bedding regularly and in hot water to remove flea eggs and dust mites.
  • Avoid harsh chemicals or grooming products that may irritate skin. Use shampoos designed to moisturize and sooth inflamed skin. Those that contain aloe or colloidal oatmeal are best.
  • Regular bathing during the worst allergy times helps physically remove the allergen from the skin. However, do not over shampoo your pet unless advised by your vet as this can strip your pets coat of natural oils and worsen their skins condition.
  • Limit access to environments where your pet seems itchier afterwards as these may contain an allergen your pet is allergic to. Rinsing off your pet with clean water can also help remove the allergen from their coat and minimize their reaction to it afterwards.
  • Improve your pets skin barrier and promote healthy skin with the use is moisturizing products and omega-3 supplements. Cats and dogs aren’t very good at converting plant oils (e.g. flax seed oil) to EPA and DHA, which are the omega 3 fatty acids most important in skin. Fish oils already contain EPA and DHA and are much more beneficial to use for our pets.
  • Reduce itch and inflammation in the skin with the use of medication. Prednisone, Apoquel and Cytopoint could be good options for your pet but will need to be prescribed by a Veterinarian.


There is no ‘one-size-fits-all’ reliable cure for itchy skin. The key is understanding the underlying cause of your pet’s condition to better manage its treatment which may include medications, dietary changes, parasite control, and/or management of underlying health conditions. By understanding the common causes of itchy skin in cats and dogs and taking proactive measures, you can help your pet enjoy a comfortable itch free life.