Blue Cross blog
What causes allergies in pets?Posted on 10 Aug 2012
Allergies are big business in both humans and animals. There are lots of “reduced allergy” products on sale, which is not surprising as allergies are becoming more common. Blue Cross chief vet Caroline Reay discusses what triggers allergies and the main culprits that cause a reaction in pets…
Allergies arise from an overactive immune system – that’s the body’s surveillance system which prevents attack by microbes.
Most microbes are harmless, but the dangerous ones can be identified by the proteins that make up their surface. Proteins are as distinct as fingerprints or barcodes.
Ideally, a surveillance system should only react to genuine threats. A fire alarm is a nuisance if it’s triggered by steam from the shower. Your body should ignore chicken proteins in food but react to nasty bugs tagging along.
When the system goes wrong it reacts unnecessarily to harmless proteins as well, causing illness. Other substances, like pollen and flea bites, can also trigger an unnecessary response.
But the system needs priming – the first few encounters with a substance don’t produce a bad reaction.
Then the reaction changes so that even tiny amounts cause a bad response. Similar to using a cashpoint and finding your card blocked by an incident of which you had no idea.
Diagnosing allergies in pets
Diagnosis is based on the pattern of disease, as tests are unreliable. An allergic dog often has itchy ears and feet, may be prone to tummy upsets, or a runny nose or eyes.
Symptoms can vary with the seasons or with stress. It’s a genetic condition passed on through the generations so affected animals shouldn’t be bred.
Susceptible animals often become allergic to more substances with time (called atopy).
Common allergies in animals
Allergies to pollen, flea bites and food are all common and often occur together in the same animal.
It’s usually proteins that are involved in food; so chicken and rice might produce symptoms whilst lamb and rice are fine.
A truly low allergy diet has stringent requirements, not just “pure” or “organic” ingredients.
It must be composed of one type of meat or fish (lamb or duck, or coley or salmon), preferably something outside the usual diet so the animal isn’t already allergic.
Alternatively, there are diets in which the protein is destroyed during manufacturing but they are not completely foolproof. Then it’s this diet and nothing else apart from water for at least six weeks.
It’s a tough condition, often expensive, difficult to treat, and hard to understand. But itching causes suffering just as much as pain and should be taken seriously.
There are kinder solutions than shutting the dog out of the bedroom at night so the scratching doesn’t keep you awake.
If you’re concerned that your pet may have an allergy, please contact your vet for advice.
For more pet health advice, have a look at our free factsheets.