An anaphylactic reaction in dogs is a life-threatening, severe allergic reaction. It happens when the immune system overreacts to an allergen (foreign substance). Luckily, anaphylactic reactions are fairly rare, but they can affect any age or breed of dog.

Common symptoms associated with anaphylactic reactions in dogs include: difficulty breathing, severe drooling and vomiting, and collapse. Dogs showing signs of an anaphylactic reaction need immediate veterinary attention. It is a true veterinary emergency. Common causes of anaphylactic reactions include stings and reactions to medications.

What is an anaphylactic reaction in dogs?

An anaphylactic reaction in dogs happens when the immune system overreacts to an allergen and causes a severe, whole-body reaction.

• What happens: A foreign substance comes into contact with the body (this can be via any route, such as ingestion or airborne). The immune system determines this substance as a threat and releases lots of chemicals, such as histamines, very quickly. This sudden release of chemicals causes the blood vessels to dilate, leading to a drop in blood pressure. Fluids start leaking into tissues, causing swelling. The airways swell and narrow, and the heart has to work harder. The body may then go into shock.

• Dogs can develop an allergic reaction to many different substances. Common causes of anaphylactic reactions include snake bites, bee or wasp stings and blood transfusions or medications.

• Anaphylactic reactions usually happen within 30 minutes of exposure to an allergen and they quickly worsen.

• Anaphylactic reactions are more common when the pet has had contact with the allergen before, i.e., after a second bee sting.

Anaphylactic reactions can be life-threatening; if your dog is showing signs of one, take them to the nearest vet. If your dog is showing mild allergy symptoms, the Joii vet team is available 24 hours a day for advice.

Symptoms of anaphylactic reactions in dogs

Anaphylactic reactions are different from chronic allergies. Though sometimes with anaphylactic shock, the initial symptoms are similar and include red, itchy skin and hives. The symptoms often quickly deteriorate and include:

• Breathing difficulties: struggling to breathe, constant panting, gasping and distress.

• Severe drooling, vomiting and diarrhoea

• Weakness

• Pale or brick-red gums

• Severe swelling of the face and neck

• Rapid heart rate

• Collapse and loss of consciousness

Are some dogs more at risk of anaphylactic reactions than others?

• Prior exposure: Dogs that have had a previous allergic reaction to an allergen are at a higher risk of experiencing an anaphylactic reaction if exposed to the same allergen again. The immune system's response can be more severe with subsequent exposures.

• Underlying health conditions: Dogs with other health issues, especially those involving the immune system, may be more prone to anaphylaxis.

• Genetic predisposition: Some dogs are more likely to react to certain medications or vaccines.

How are anaphylactic reactions diagnosed in dogs?

Diagnosing anaphylactic reactions in dogs is difficult. Vets will often diagnose based on the symptoms the pet is showing and the speed of onset.

After emergency treatment, the following tests may be recommended:

• Blood and urine tests

• Imaging (x-rays, ultrasound)

In the long term, investigation into allergies may be advised, such as:

• A food trial

• Allergy testing: blood or skin tests

What’s the treatment for anaphylactic reactions in dogs?

Dogs showing signs of anaphylactic shock require emergency treatment for stabilisation. Treatment often includes:

• Oxygen therapy

• Assisted breathing

• Emergency medications, given into the vein

• High doses of fluids, given into the vein

• Hospitalisation for monitoring for a minimum of 24 hours

How to look after a dog at home after an anaphylactic reaction

When your dog is well enough to come home, you can help them recover by:

• Allowing rest in a comfortable and quiet area of the home

• Making sure they are eating and drinking

• Giving any prescribed medications at the correct times and doses

• Closely monitoring to make sure they do not develop any new symptoms

Tips on how to prevent anaphylactic reactions in dogs

Unfortunately, many anaphylactic reactions are unavoidable. Where possible:

• Monitor your dog when they are outdoors.

• Avoiding known triggers: Allergy testing via skin or blood tests can help determine what allergens to avoid in food and the environment.

• Be aware of the signs and what to do if they occur.

• Feed your dog a complete and balanced diet to ensure a healthy immune system.

• Avoid sudden diet changes and giving your dog human food.

When to worry about anaphylactic reactions in dogs

Seek help from a vet in practice immediately if your dog shows any signs of an anaphylactic reaction.

• Breathing difficulties: struggling to breathe, constant panting, gasping and distress.

• Severe drooling, vomiting and diarrhoea

• Weakness

• Pale or brick-red gums

• Severe swelling of the face and neck

• Rapid heart rate

• Collapse and loss of consciousness

Speak to one of our Joii vets for advice if your dog has chronic allergies.