Allergic reactions can be mild or severe. Common signs of an allergic reaction include hives and swelling of the face.

dog with allergic reaction hives swelling eyes and face

Some allergic reactions can become very serious or even fatal; if you notice weakness or vomiting with an allergic reaction, this can be a sign of anaphylactic shock, which is a true emergency.

dog with allergic reaction hives swelling eyes and face

This little gal was treated for very severe anaphylactic shock. You can see her face was swollen, and her heart rate was over 200 beats per minute, because her blood pressure was so low that her heart had to beat much faster keep up.

Both of these guys made a full recovery.

From our TWIN TREES VET TALK series:


In this video we discuss rashes. The golden rule is that you can never be 100% sure what a rash is based on its appearance. There are many different causes of a rash (some are less serious, some are more serious), and so your veterinarian may need to run some diagnostic tests to get a better understanding of what is causing the rash. Hives are a common rash that result from an allergic reaction. Allergic reactions can be mild or severe and life-threatening (anaphylactic shock), so it is best to see your vet right away. If you are in the woods or camping, the first line of treatment for an allergic reaction is to give regular Benadryl (Diphenhydramine HCl) at a dose of 1 mg per pound orally every 8 hours. Never give non-drowsy antihistamines to a pet, as these are toxic and can cause seizures, cardiac arrhythmias and death. Depression, vomiting, weakness, shaking, and laboured breathing are all signs of a more severe reaction (anaphylactic shock), which is an emergency. Another common rash is pyoderma (caused by bacterial infection of the skin). If you are far from a vet, you can gently cleanse the area 2-3 times per day using chlorhexidine gluconate (the 2% or 4% solution), which can be purchased at the pharmacy. If you have any concerns about your pet (vomiting, weakness, depression, poor appetite, discomfort, itchiness), it is best to see your veterinarian right away.