We are more conscious of serious allergies in people nowadays, but what about pets? What is anaphylactic shock and can dogs suffer from it? We’ll take a look at this as well as what to do if you are concerned about your furry friend.

What is anaphylactic shock?

Anaphylactic shock is a serious and sometimes fatal reaction occurring soon after contact with an allergen (usually a protein of some kind). There is a whole array of allergens in people, but common examples include peanuts, insect stings and shellfish. This type of allergic reaction is a true medical emergency and requires immediate treatment as swelling can quickly develop in the patient’s airways.

Anaphylaxis is an overreaction of the immune system to something foreign, also known as a type 1 hypersensitivity reaction. Patients must have had some exposure to this allergen in the past, usually resulting in a mild or localised reaction.

In susceptible individuals, their immune system becomes sensitised meaning that their body will recognise the allergen the next time it is encountered and have an exaggerated reaction. This abnormal immune response leads to the release of massive amounts of histamine into the body; which causes a drop in blood pressure, contraction of smooth muscles and swelling to occur. If prompt treatment isn’t received this type of reaction can result in death.  

Can dogs suffer from anaphylactic shock?

Yes, dogs can also suffer from anaphylactic shock, but thankfully it is rare.

In dogs, the most common things to cause this type of reaction would be insect stings, an injection (vaccinations or medication) or an immediate reaction to a food allergen. A localised allergic reaction is far more common in dogs, such as itchiness or hives, particularly if the allergen has entered via the skin.

If a dog suffers from anaphylaxis, this is a ‘body-wide’ reaction. The liver is the primary organ that is affected by excessive amounts of histamine release, rather than the lungs (as it is in people). This leads to the rapid onset of some serious gastrointestinal symptoms, rather than the classic breathing issues we see in people.

What are the symptoms of anaphylactic shock in dogs?

The following symptoms may be seen in dogs experiencing anaphylaxis, usually within seconds or minutes of encountering the allergen –

  • Diarrhoea
  • Vomiting
  • Drooling
  • Pale gums
  • Cool extremities
  • Elevated heart rate
  • Seizures
  • Collapse
  • Death

What should I do if I suspect my dog is having an allergic reaction?

As mentioned earlier, most dogs having an allergic reaction will just have a localised one resulting in a few skin changes. Hives might be noted, which are areas of swelling in the skin causing lumps and bumps to appear. These may be quite small and subtle, making areas of the fur stand up slightly. Or in some cases, widespread swelling might be noted. This is most common in the muzzle, head and neck area and can look quite dramatic. Hives and swelling typically disappear by themselves again when the allergen is no longer present. Vets can help ease the symptoms though using antihistamines or steroid medication.

If your dog has some dramatic symptoms shortly after contacting an allergen then this is an emergency and you need to get your dog to a vet as soon as possible. Time is of the essence.

Treatment for anaphylaxis involves intravenous fluids to help correct blood pressure issues, doses of intravenous adrenaline and taking measures to ensure the airways stay open if required (passing a breathing tube). Additional medications such as corticosteroids and atropine may be needed too. Unfortunately, a minority of patients will not survive, despite everyone’s best efforts. 

How can I prevent allergic reactions in the future?

It can be hard to prevent allergic reactions altogether, not least because there are often instances where a clear allergen isn’t identified. In many cases, it is just assumed to have been an insect sting or bite. Obviously, if you can identify a trigger, like a certain cleaning product or food item then you can try to avoid these around your pet going forward.

As discussed earlier, a dog’s first allergic reaction might be a relatively mild one, but there is a risk that any subsequent ones could become more serious. This isn’t always the case though, and anaphylactic shock in dogs is extremely uncommon.

If your dog is having recurrent reactions or ongoing skin symptoms (like itchiness or redness), then your vet will discuss longer-term allergy management and medications.


While dogs can suffer from anaphylactic shock, it is an extremely rare occurrence. Most dogs will have localised allergic reactions, which tend to be self-limiting. If you have any concerns about your pet at all, then always contact your vet – it is always better to be safe than sorry!

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