Allergic reactions can happen

Although many puppies seem to barely notice when their puppy shots are given, and show no ill effects afterwards, it's not unusual for a pup to have an allergic reaction of some sort.

Most of the time these reactions to puppy vaccinations are mild, and last only a day or two. But occasionally they can be severe enough to need veterinary attention.

Being aware of the potential problems is helpful. These sort of reactions can be:

  • Mild
    Most reactions are mild and symptoms can include a slight fever, lethargy or a depressed appearance and/or decreased appetite. Most of these type of symptoms are short lived (but can appear several days to weeks after the puppy shots were given). They usually don't need veterinary treatment.

  • Moderate
    Symptoms of a more serious allergic reaction to puppy immunizations usually involve swelling and/or hives. Often particularly noticeable around the mouth, face and neck, although welts can appear anywhere on your puppy's body.

    This kind or reaction usually occurs within a few hours of the vaccination. It can progress and become severe, so if you notice any swelling or hives appearing on your pup, take him back to the veterinarian's office right away. Treatment usually involves steroids and maybe anti-histamines.


  • Severe
    The most serious allergic reaction to puppy shots is anaphylaxis. This is a life-threating condition which usually strikes within minutes of the vaccine being given. It may start out with vomiting/diarrhea and a loss of balance. It causes a sudden drop in blood pressure and swelling which can result in breathing difficulties, seizures and even death.

    It's an emergency situation and if you have already left the veterinarian's office you need to return there immediately. your puppy may need oxygen, IV fluids or other medical intervention.

Luckily moderate to severe allergic reactions to puppy shots are pretty rare and are generally much less of a danger to your puppy than the diseases they prevent.

There seems to be a higher incidence of allergic reaction to the vaccines for Rabies, Parvo and Leptosirosis.

There are some dog breeds that are more prone to these kind of reactions than others. They include, but aren't limited to, Miniature Dachshunds, West Highland White Terriers, Old English Sheepdogs, Akitas, Portuguese Water Dogs, Weimaraners, and Harlequin Great Danes.

The bottom line is that you need to watch your puppy closely for the first day or so after he's had his puppy shots. Any major reaction is most likely to occur within 24 hours (often much sooner). An allergic reaction of any sort is unlikely to happen after the first shot though, it's subsequent ones that you should pay particular attention to.