Hay Fever In Cats – Causes, Symptoms & Treatment

What is hayfever?   Symptoms   Diagnosis   Treatment

Hay fever in cats

Image courtesy Chad Horwedel.

What is hayfever?

Allergic rhinitis is an allergic reaction affecting mostly the nose. Hay fever is a type of allergic rhinitis, as the name would suggest, it is most often associated with allergies to pollens.  There are four types of allergies to affect cats.

  • Food – As the name would suggest, this is an allergy to food. This is the most common type of allergies in cats.
  • Contact – This type of allergy is rare in cats, this type of allergy occurs when the cat comes into contact with an allergen, for example, wool, or medications.
  • Insect – The most common cause of insect allergy is cat fleas but other insects can also cause allergies.
  • Inhalant –  Unlike in humans who tend to develop hay fever (allergic rhinitis),  most cases of inhalant allergy in cats present as skin conditions. However, in some cats, the nose is primarily affected. Hay fever is a type of inhalant allergy.

Hay fever occurs when the cat’s body reacts to a pollen, common allergens include grasses. Exposure occurs when the cat either inhales the pollen or licks it during grooming. Usually, the body would ignore a benign substance such as pollen, however, in some cats, the immune system mounts an unnecessary allergic response. Anything the body has an allergic reaction to is known as an allergen. Below is a simplified step by step guide to how an immune response occurs.

  • The first step is sensitisation. So, a foreign substance enters the body (in this case some pollen, via the nose), and cells called macrophages which are scavenger cells break up the invader. They then display the fragments of the invader on their cell walls for white blood cells (known as T cells).
  • T-cells then secrete a chemical which activates another type of white blood cell known as B cells. These cells generate antibodies specific to that particular invader. These antibodies are known as immunoglobin E (IgE). These antibodies are attached to immune cells called mast cells and basophils. Mast cells are found in the tissues and basophils in the blood.
  • The next time that particular foreign substance enters the body, the IgE cells on mast cells recognise the invader and attach to them. When this occurs, mast cells and basophils release a chemical substance known as histamine. Histamine causes capillaries in the nose to dilate (swell), causes redness, nasal secretions, swelling, and inflammation.


Depending on the allergen involved, symptoms may be seasonal, particularly if it’s pollen related. Spring and summer are when pollen levels are at their highest.

The most common symptoms of hay fever in cats are a runny nose and sneezing. Other symptoms may include:

  • Red, itchy, watery eyes.
  • Pawing at the face.
  • Noisy breathing.
  • Blood may be seen in the nasal discharge after prolonged exposure due to blood vessels becoming damaged.
  • Some cats may develop skin conditions, including lumps and bumps, itching, redness, and swelling.

As you can see, many of these symptoms are similar to that of a cat cold or flu, but shouldn’t include fever or loss of appetite. While extremely irritating to your cat, he shouldn’t appear unwell.


Your veterinarian will perform a complete physical examination of your cat and obtain a medical history from you. Hay fever will be suspected if there is a history of seasonal rhinitis.

If an allergy is suspected, your veterinarian may decide to perform a ‘skin prick test’, which involves injecting a small amount of several common allergens into the skin and watching for a local reaction, which presents as a red and swollen patch.


Minimising contact with the allergen is the main goal as well as controlling symptoms. Obviously, it is not always easy to avoid exposure to pollens. Keeping windows shut, use air filters, regularly dust can reduce exposure.

Steroids to control inflammation and suppress the immune system. Steroids may be administered by oral tablet or injection. The use of steroids in cats needs to be carefully monitored by your veterinarian and your cat should be put on the lowest dose possible to manage symptoms.

Allergen immunotherapy (allergy shots). These shots expose the cat to a tiny amount of the allergen, gradually increasing the amount given, this can help the cat’s body get used to the allergen and reduce symptoms. The success rate is varied.

Keeping your cat indoors as much as possible during high pollen season. Pollen counts are at their highest from dawn to around mid-morning.

Medicated shampoos and conditioners can be used to clean the coat of pollens,  reducing the amount that is inhaled and ingested during grooming. This can also help to soothe inflamed and itchy skin.

Antihistamines are medications which block the effects of histamines and may be prescribed to offer relief to your cat. These medications are the same type that is used to treat allergies in humans. However, it is vital you speak to your veterinarian about the appropriate antihistamine to use as not all are suitable, particularly if your cat has an underlying medical condition.