Rabies Vaccine Allergies in Dogs

Rabies vaccinations are something that almost every dog receives in their yearly trip to the veterinarian, and sometimes every 3 years. These vaccines are meant to prevent the horrible and incurable disease that plagues wildlife and unfortunately spreads to domestic animals such as cats and dogs. As with many things that are meant to help, they sometimes have side effects. Your dog can react to anything that enters their body that their immune system deems unsafe, but when it comes to vaccines many times veterinarians must work past the allergy to prevent a disease.

An allergic reaction to the rabies vaccine is your dog’s immune system having a hypersensitive response to the vaccine itself. Symptoms can range from skin rash to diarrhea, and in very rare cases acute kidney failure.

Your dog’s symptoms may not always be the same as what other dogs may experience. If you suspect your dog is having an allergic reaction to a vaccine, contact your veterinarian. Symptoms may or may not include the following:

• Discomfort and swelling at the site of injection 
• Mild fever
• Lack of appetite
• Decrease in activity or desire to play
• Swelling of face, eyes, and ears 

It is important to note that swelling at the injection site is somewhat common and may last up to a week after shot is received, though it should still be reported to the clinic. If the site begins to appear infected or an abscess forms, your pet should be seen by your veterinarian. If a tumor grows at site of injection, report it to the veterinarian.

Rare and more serious symptoms may occur within a few minutes, hours or days of the vaccination. If any of the following symptoms develop, seek veterinary attention immediately. 

• Vomiting 
• Diarrhea 
• Hives or itchy skin 
• Collapse 
• Respiratory distress

Types

Hypersensitivity, or allergic reaction, could be a result of the vaccine antigen or other minerals and proteins found in the vaccine. BSA (otherwise known as Fraction V or Bovine Serum Albumen) and Fibronectin are proteins usually derived from cows that are used in vaccines and have been known to have antibody reactions from dogs. 

• Type 1 - Acute anaphylaxis: angioedema (large welts), anaphylaxis or shock, and death
• Type 2 - Cytotoxic reactions of the Type 2 variety can be the cause of several different diseases in dogs such as blood clotting issues, muscle and skin disorders, and anemia
• Type 3 - Cutaneous ischemic vasculopathy which has been associated with the rabies vaccine can occur at the site of injection or another, more distant location such as the tips of the ears; this is known as the immune complex

Your dog’s body has a wonderful defense system to keep it safe from the many things that could make him sick, this is called the immune system. The immune system attacks anything that enters your dog’s system that it feels will cause it harm to the body, sending antibodies to attack the foreign substance. Unfortunately, sometimes it will attack things that are actually meant to help, such as vaccines. This is the same process that causes some dogs to react to seasonal allergens such as pollen. There are many things that can cause an allergic reaction in your dog; here is a brief list of some allergens your pet could develop or currently have: 

• Bee stings
• Vaccines
• Protein sources (i.e. chicken and/or beef) 
• Pollen (seasonal)

Most symptoms of an allergic reaction are easily diagnosed just through visual signs and symptoms. Many veterinarians warn clients of common reactions to vaccines that many pets have that are not cause for alarm such as mild lethargy, lack of appetite (only for 1 or 2 meals), mild pain at injection site, lack of desire to run and walk, and even sometimes a mild fever. These sometimes may last 1-2 days after the vaccines are given, however an allergic reaction to a vaccine may show before you even leave the clinic. Facial swelling or swelling of the ears will many times be a red flag and will cause your veterinary caregiver to take a second look. If symptoms occur a day or so later then your veterinarian may explore other options by testing with bloodwork to confirm that it isn’t something more serious, especially if your dog has had one or more severe symptoms.

If your canine immediately shows symptoms after the injection is given your veterinarian will, in many cases, inject either an antihistamine, corticosteroids, or epinephrine to calm the side effects. What your veterinarian chooses will be based on the severity of side effects. Your pet may also require IV fluids and oxygen, and if necessary ventilation and endotracheal intubation may be performed. In less urgent cases dexamethasone or diphenhydramine are given. When in the late stages of reaction to the substance, oral corticosteroids or antihistamines are usually prescribed for 2-3 days. 

Monitor your dog for the next week after reaction occurs for previous symptoms such as hives or vomiting and diarrhea to arise again. If symptoms return contact your veterinarian.

If your dog should have an allergic reaction to any medication or vaccine, always alert your veterinarian and ask that a note be made in their file. Your dog may have to be dosed with an antihistamine or an anti-inflammatory drug (NSAID) prior to vaccinations for the rest of his life to prevent reactions to the vaccine itself. For the safety of yours and other animals, rabies shots are required at the minimum for dogs in most states. It is rare that states give an exemption to the rabies vaccination by the authority of your veterinarian. Though in some states it is allowed if a veterinarian determines that, for health reasons, the dog should no longer receive said vaccine until the patient is deemed healthy enough to receive the vaccination again.  The veterinarian may also request that your pet stay in the office up to 30 minutes after your appointment has finished to monitor your dog’s reaction to the vaccination. 

In some cases, your veterinarian may choose to continue using the same vaccine type, but from a different manufacturer, though it should be noted that the same proteins that caused a reaction in one vaccine may very well be present in another and so changing the manufacturer does not guarantee that your pet will not have a reaction. Depending on the severity of the reaction, once medication is given, your pet may improve within 15-30 minutes.

Routine vaccinations can be expensive but aren’t usually covered by pet insurance. The good news is, wellness plans can put 100% of the bill right back in your pocket within 24 hours. Check out our pet wellness plans to find the right match for your pet!