How Long Does A Vaccine Lump Last in Dogs? When To Worry?

Taking dogs to vaccination sites for better health and safety is to be expected from any responsible pet owner.

However, what ignites heated discussion is the big vaccine lumps that form on the dog’s central body after being vaccinated.

Are these lumps normal? How long does a vaccine lump last in dogs? These burning questions have been plaguing many dog parents for months.

But no worries; my article has all the answers you need. Keep scrolling.

Are Vaccine Lumps Normal for Dogs? 

how long does a vaccine lump last in dogs

People have been worrying about these firm lumps, assuming they signify severe, hidden health issues not yet discovered by the vets.

As someone who owns three dogs, I can assure you they are perfectly normal.

Why, though? Why does my dog have a lump after shots?

Think about it: vaccines in nature are expected to stimulate immune systems, which explains the presence of small-sized lumps after vaccination. More specifically: 

  • Your dog’s immune system gets active after the injection, causing the immune cells to infiltrate and produce small lumps.
  • The lymph nodes (near injection sites) are activated upon injection and grow larger.

My dogs experienced all these common responses and have undergone no complicated medical issues thus far. Trust me; there is nothing you should worry about.

How Long Does A Vaccine Lump Last in Dogs?

The consensus is about 14 days or 2 weeks, which applies to all vaccines and medicines used to treat your dog. Remember to give your dog no special treatments or diets during these periods.

Leave them on their own and treat them as you always do until the lumps gradually shrank and disappeared completely.

More attention will be required if the lump after vaccine dog persists for over 2 weeks.

And if they are still visible after 3 weeks – accompanied by clear signals of pain and uneasiness – it’s time to take your dog to the nearest clinic! 

Aside from vaccination pumps, your dogs might also encounter some other minor side effects after immunization, including: 

  • Signs of swelling, tenderness, and redness at their vaccination spots
  • Mild symptoms of fatigue and decreased activity level
  • Appetite loss
  • Low-grade, mild fever
  • Coughing, sneezing, nasal discharge (any other respiratory signals) due to intranasal vaccine sprayed/dropped via nostrils, which often lasts a couple of days.

Except for the last symptoms, the rest mentioned on my list never lasts more than 1 day.

So if they do not go away after 24 hours and make your pet extremely uncomfortable, report the problem to a trusted veterinarian.

When Should You Take The Dogs To The Vet To Treat Large Lump On Dog After Vaccination? 

why does my dog have a lump after shots

As mentioned above, firm bumps lasting longer than three weeks are abnormal, requiring immediate medical treatment before they worsen.

Their sizes also play a part: knots larger than 0.7 inches in diameter (or approximately 2 cm) indicate serious issues. 

Most importantly, watch out for other side effects; vaccine reactions are normal, but EXTREME, adverse reactions are another story.

If your dogs suffer from at least one of these following signals for prolonged periods, take them to veterinary clinics: 

All these indicators are parts of canine anaphylactic reactions -directed against tissue laboratory, preservatives, virus vaccine stabilizers, and infectious organisms.

Listed by experts as among the most life-threatening and extreme forms, they get even worse at constant exposure to offending protein.

Only inexperienced dog owners would underestimate their detrimental effects!

Aside from Lumps and Minor Side Effects, What Are Other Symptoms to Expect After Vaccination?

Certain behavioral changes can be identified, which, in most cases, are nothing serious or threatening.

As the vaccination lumps on one of their legs feel itchy, your pets would avoid using that leg altogether and try to run or chase other animals with their other three limbs.

But it’s a different story if you notice your four-legged friend gets itchy and scratches other areas like his privates. So pay close attention!

Or, if your canine feels a little nauseous after an intense vaccine shot, it might prefer to lie down during most of its play hours. 

All of these scenarios would be quite worrying if they occurred at any other time – but after vaccination, such reactions are unsurprising. Just wait a day (or even a few hours), and they will return to normal.

If the dogs still act strange, refer to my guide above to identify severe symptoms/persistent lumps and bring them to the hospital as soon as possible.

FAQs: Extra Medical Advice

lump after dog vaccine

What Breeds Are Prone to Core Vaccine Lumps? 

A few scientific studies have concluded the following breeds to be most susceptible to dog vaccine lump and reactions:

  • Pugs
  • Dachshunds
  • Miniature Pinschers
  • Boston Terriers
  • Chihuahuas

The studies claimed that genetic predisposition might be part of the reason.

More specifically, they have discovered evidence that links certain distemper vaccines with HOD (hypertrophic osteodystrophy), a developmental and chronic disease that destroys growth plates in these growing dogs.

Nevertheless, I suggest taking these information tidbits with a pinch of salt.

Other studies on the same topic have been released with conflicting results, meaning scientists have not yet reached their final conclusion about whether vaccination contributes to HOD.

Can The Lump After Dog Vaccine Go Away On Their Own? 

Yes, most of the time, as I already mentioned. Common vaccine lumps do not pose any serious threat; they are just minor reactions after your dog’s immune system is triggered.

Still, some exceptions are recorded. Serious medical problems aside, there are cases where the lumps do not cause any health complications – yet refuse to disappear regardless.

In those cases, owners will be asked to monitor the lumps for a couple weeks and take note of unusual symptoms in the dog’s preferred diet, sleeping schedules, or physical health.

Once your vet is certain that nothing else went wrong, the dog would then be subjected to a minor surgical treatment to remove the lump completely.


How long does a vaccine lump last in dogs? My detailed analysis hopefully can lift the curtain of confusion for worrying dog owners.

If your dog has lump after shot, relax; these spots will likely go away on their own!

Please get in touch with me for more discussion if there are still aspects I have yet to mention. I’m all ears!


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Hi I am Mitchell. Dog Growth is a blog about dog caring and training where I share my experiences to my community. Hope you enjoy it!

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