What are allergies and how do they affect cats?
One of the most common conditions affecting cats is allergy. An allergy occurs when the cat’s immune system “overreacts” to foreign substances called allergens or antigens. Those overreactions are manifested in one of three ways. The most common manifestation is itching of the skin, either localized in one area or a generalized reaction all over the cat’s body. Another manifestation involves the respiratory system and may result in coughing, sneezing, and wheezing. Sometimes, there may be an associated nasal or ocular (eye) discharge. The third manifestation involves the digestive system, resulting in vomiting, flatulence or diarrhea.
How many types of allergies are there and how are they each treated?
There are four known types of allergies in the cat: contact, flea, food, and inhalant. Each has common clinical signs and unique characteristics.
Contact Allergy
Contact allergies are the least common of the four types of allergies in cats. They result in a local reaction on the skin. Examples of contact allergy include reactions to flea collars or to types of bedding, such as wool. If the cat is allergic to such substances, there will be skin irritation and itching at the points of contact. Removal of the contact irritant solves the problem. However, identifying the allergen can be challenging in many cases.
Flea Allergy
Flea allergy is the most common allergy in cats. A normal cat experiences only minor irritation in response to flea bites. The flea allergic cat, on the other hand, has a severe, itch-producing reaction when the flea’s saliva is deposited in the skin. Just one bite causes such intense itching that the cat may severely scratch or chew itself, leading to the removal of large amounts of hair. There will often be open sores or scabs on the skin, causing a secondary bacterial skin infection. The area most commonly involved is over the rump or base of the tail. In addition, the cat may have numerous, small scabs around the head and neck. These scabs are often referred to as miliary lesions, a term which was coined because the scabs look like millet seeds.
The most important treatment for flea allergy is to eliminate all fleas. Therefore, strict flea control is the backbone of successful treatment. Unfortunately, this is not always possible in warm and humid climates, where a new population of fleas can hatch out every fourteen to twenty-one days. However, the new topically applied monthly flea products may kill fleas before they have a chance to bite your cat. When strict flea control is not possible, injections of corticosteroids, also referred to as “cortisone” or “steroid shots”, can be used to block the allergic reaction and give immediate relief. This is often a necessary part of dealing with flea allergies. Fortunately, cats appear relatively more resistant to the side-effects of steroids than other species. If a secondary bacterial infection occurs, appropriate antibiotics must be used.
Inhalant Allergy
Inhalant allergy or atopy is estimated to be the third most common type of allergy in cats. Cats may be allergic to all of the same inhaled allergens that affect us. These include tree pollens (cedar, ash, oak, etc.), grass pollens (especially Bermuda), weed pollens (ragweed, etc.), molds, mildew, and the house dust mite. Many of these allergies occur seasonally, such as ragweed, cedar, and grass pollens. However, others are with us all the time, such as molds, mildew, and house dust mites. When humans inhale these allergens, we express the allergy as a respiratory problem. Atopy is sometimes called “hayfever.” The cat’s reaction, however, usually produces severe, generalized itching.
Most cats that have an inhalant allergy are allergic to several allergens. If the number of allergens is small and they seasonal, itching may last for just a few weeks at a time during one or two periods of the year. If the number of allergens is large or they are present year-round, the cat may itch constantly.
