Overview

Pet allergy is an allergic reaction to proteins found in an animal's skin cells, saliva or urine. Signs of pet allergy include those common to hay fever, such as sneezing and runny nose. Some people may also experience signs of asthma, such as wheezing and difficulty breathing.

Most often, pet allergy is triggered by exposure to the dead flakes of skin (dander) a pet sheds. Any animal with fur can be a source of pet allergy, but pet allergies are most commonly associated with cats and dogs.

If you have a pet allergy, the best strategy is to avoid or reduce exposure to the animal as much as possible. Medications or other treatments may be necessary to relieve symptoms and manage asthma.

Symptoms

Pet allergy signs and symptoms caused by inflammation of nasal passages include:

Sneezing

Runny nose

Itchy, red or watery eyes

Nasal congestion

Itchy nose, roof of mouth or throat

Postnasal drip

Cough

Facial pressure and pain

Frequent awakening

Swollen, blue-colored skin under your eyes

In a child, frequent upward rubbing of the nose

If your pet allergy contributes to asthma, you may also experience:

Difficulty breathing

Chest tightness or pain

Audible whistling or wheezing sound when exhaling

Trouble sleeping caused by shortness of breath, coughing or wheezing

Skin symptoms

Some people with pet allergy may also experience skin symptoms, a pattern known as allergic dermatitis. This type of dermatitis is an immune system reaction that causes skin inflammation. Direct contact with an allergy-causing pet may trigger allergic dermatitis, causing signs and symptoms, such as:

Raised, red patches of skin (hives)

Eczema

Itchy skin

When to see a doctor

Some signs and symptoms of pet allergy, such as a runny nose or sneezing, are similar to those of the common cold. Sometimes it's difficult to know whether you have a cold or an allergy. If symptoms persist for more than two weeks, you might have an allergy.

If your signs and symptoms are severe — with nasal passages feeling completely blocked and difficulty sleeping or wheezing — call your doctor. Seek emergency care if wheezing or shortness of breath rapidly worsens or if you are short of breath with minimal activity.

Causes

Allergies occur when your immune system reacts to a foreign substance such as pollen, mold or pet dander.

Your immune system produces proteins known as antibodies. These antibodies protect you from unwanted invaders that could make you sick or cause an infection. When you have allergies, your immune system makes antibodies that identify your particular allergen as something harmful, even though it isn't.

When you inhale the allergen or come into contact with it, your immune system responds and produces an inflammatory response in your nasal passages or lungs. Prolonged or regular exposure to the allergen can cause the ongoing (chronic) airway inflammation associated with asthma.

Cats and dogs

Allergens from cats and dogs are found in skin cells the animals shed (dander), as well as in their saliva, urine and sweat and on their fur. Dander is a particular problem because it is very small and can remain airborne for long periods of time with the slightest bit of air circulation. It also collects easily in upholstered furniture and sticks to your clothes.

Pet saliva can stick to carpets, bedding, furniture and clothing. Dried saliva can become airborne.

So-called hypoallergenic cats and dogs may shed less fur than shedding types, but no breed is truly hypoallergenic.

Rodents and rabbits

Rodent pets include mice, gerbils, hamsters and guinea pigs. Allergens from rodents are usually present in hair, dander, saliva and urine. Dust from litter or sawdust in the bottom of cages may contribute to airborne allergens from rodents.

Rabbit allergens are present in dander, hair and saliva.

Other pets

Pet allergy is rarely caused by animals that don't have fur, such as fish and reptiles.

Risk factors

Pet allergies are common. However, you're more likely to develop a pet allergy if allergies or asthma runs in your family.

Being exposed to pets at an early age may help you avoid pet allergies. Some studies have found that children who live with a dog in the first year of life may have better resistance to upper respiratory infections during childhood than kids who don't have a dog at that age.

Complications

Sinus infections

Ongoing (chronic) inflammation of tissues in the nasal passages caused by pet allergy can obstruct the hollow cavities connected to your nasal passages (sinuses). These obstructions may make you more likely to develop bacterial infections of the sinuses, such as sinusitis.

Asthma

People with asthma and pet allergy often have difficulty managing asthma symptoms. They may be at risk of asthma attacks that require immediate medical treatment or emergency care.

Prevention

If you don't have a pet but are considering adopting or buying one, make sure you don't have pet allergies before making the commitment.