Pet allergy – can I still have a dog?

Allergies in the human population are rising. More than 1 in every 10 people have an allergy of some kind! Domestic pets are one of the most common indoor allergens reported worldwide.

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Pet allergies are caused by reactions to specific proteins found in the animal’s saliva, urine, hair and dander (old skin cells and dried saliva). In dogs, these proteins are thought to be mostly found in hair and dander. People who are allergic to dogs react more strongly to these proteins than non-allergic people.

There are 7 different proteins in dogs that can cause allergies in people, and these are named Can f 1-7. It is unclear if any are more likely to cause an allergic reaction than the others.

Dogs shed large amounts of these proteins in the hair and dander into the environments. They can remain airborne, settle into dusty areas, or ‘stick’ to surfaces such as furnishings, clothes and objects. This means that dog dander and hair can be found in environments in which no dog is living, although homes with a resident pet do have much higher levels.

Allergies can develop in babies and children, or can develop later in life as adults. However, once the allergy has developed you are likely to react any time you are exposed to a trigger. Signs of an allergy can take between minutes to hours to appear after coming into contact with the allergen. The pet does not actually need to be present for a reaction to develop; allergens can be present in the air or in the environment, such as dander or saliva on clothing or furniture.

The main symptoms are:

• Sneezing.
• Runny nose.
• Nasal congestion.
• Post-nasal drip.
• Red, sore and itchy eyes.
• Cough/wheeze.
• Red, sore or itchy skin on the face, chest, or any skin which has been in contact with the dog or its environment.

These symptoms can be seen together or separately and can vary in severity.

As with any allergy, there are multiple components to management, including: reducing exposure, medications and immunotherapy.

Reduce exposure to the allergen

Houses with pet dogs will have much higher levels of the Can f proteins than other houses. Since these proteins can remain in the environment for many months or years, even if the pet is removed, an allergic reaction could continue.

However, there are ways to reduce the amount of allergen in the home, especially in key areas.

Inside the home:

• Limit access of the pets to certain rooms in the house. Dander and hair can still spread, but keeping pets away from key areas such as beds and sofas will reduce allergen levels in living spaces.
• Keep windows open where possible to increase ventilation.
• Remove carpets and replace with hard floors.
• Wash bedding and curtains frequently.
• Wash/wipe down hard surfaces and floors frequently.
• Vacuum floors and furniture twice weekly, with a vacuum cleaner which has a high-efficiency particulate air filter (HEPA).
• Use HEPA filters in the house.
• Use laminar airflow over beds at night.
• Maintain excellent hygiene around the pets – hand washing, etc.
• Frequent washing and grooming of the pet by a non-allergic person can reduce allergen shedding – this needs to be done at least twice weekly to have an impact on allergen levels.

Outside the home:

• Avoid visiting homes where pets are present.
• If exposure is likely, minimize contact and wash thoroughly afterwards.

Immunotherapy

The basis of immunotherapy is to expose an allergy sufferer’s immune system to tiny amounts of the allergen, and then slowly increase this amount until their system becomes more tolerant to the proteins. There is evidence that this can be effective for dog allergy treatment, but research is still in its early days.

Medication

Various medications are available to relieve the symptoms of pet allergies, including antihistamines. Speak to a pharmacist, doctor or other medical professional for advice.

There are various breeds of dog which are often described as ‘hypoallergenic’, ie produce less allergens than normal dogs. These might be more suitable to be owned by people with dog allergies. However, allergen levels vary hugely both between breeds but also between individuals of each breed. It has been shown that the level of the Can f 1 protein in the hair and coat of ‘hypoallergenic’ breeds such as the Poodle and Labradoodle is similar to those of ‘normal’ breeds such as the Labrador Retriever. A short hair coat and lack of shedding were thought to be protective for sufferers with allergy as the pet allergens are carried in hair and dander. Unfortunately, it has been shown that levels of allergen in floor and airborne dust in households with these ‘hypoallergenic’ breeds were no different from those with normal breeds. It is likely that the breed of dog chosen has little part to play in allergy management.