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Puppy has red, crusty neck lump after vaccine. When to see vet?

Updated on September 23rd, 2025

Pet's info: Dog | Mixed Breed | Male | unneutered | 1 month and 13 days old | 0 lbs

My puppy is 7 weeks old and he has a bump or lump on the back of his neck. It looks red and crusty when I look at it. He had his first vaccine 2 days ago and I know that lumps can be caused after a vaccine but its red and crusty like a scab over the bump. I can attach a photo but it's kinda hard to tell what it might be. It could just be that he had a reaction or he scratched himself and that might be what caused the scab. Just wanted to see what you recommend and if I should see a vet or wait?

4 Answers

Most Helpful Answer

Answered By Dr. Strydom, DVM

Veterinarian

Published on October 6th, 2017

You're right it is hard to tell from the photos. I think it looks more like mange. The unfortunate thing is that many skin issues look similar so it is often difficult to tell exactly what it is just by looking at it. I can say that I have not had a vaccine reaction look that way so I think that is less likely. Also, vets don't usually use the back of the neck for vaccinating anymore - are you sure the vaccine was given there?

I don't think it's an emergency. I would recommend putting some Neosporin on it for now and then just bring it up at the next vet exam. He should be due for booster vaccines in a few weeks. If it starts looking worse or it is bothering him then I would take him in to see the vet sooner.

Hope this helps. Best wishes.

1Pet Parents found this answer helpful

Related Answers from Veterinarians

Answered By Dr. Melanie, BVSc MS
Veterinarian
Published on November 21st, 2020
I'd just keep an eye on the area for now. Clean it with warm water and antiseptic soap. Keep the wound clean and dry, and monitor it for signs of infection. If you see redness, swelling, warmth to the touch, or pus, then it is infected and Sweetheart will need to see the vet for antibiotics to treat it. I hope this helps!
1Pet Parents found this answer helpful
Answered By Megan, DVM, CVA
Veterinarian
Published on December 13th, 2017
This is a common location for a vaccine to be given. Has he recently had puppy vaccines? If so, this is likely just a local reaction and no big deal. You can keep watching it. If he hasn’t had shots recently or if you don’t think a vaccine was given there or if it is growing, I would have your vet take a look at it before his next set of shots. Your vet will be able to do a cytology if needed and determine the type of mass it is. I hope this helps!
1Pet Parents found this answer helpful
Answered By Ann Dion, DVM
Veterinarian
Published on November 25th, 2018
Hello and welcome to Petco Pet Education Center, formerly Petcoach.

Lumps and bumps can be many different things, including inflammation (reaction to vaccine is possible), infections (this could be a small pocket of pus), tumors that are both cancerous and not-cancerous, foreign objects stuck inside the body causing inflammation/infection, etc.

I recommend you have your boy back to your vet where you had the vaccine and have them check to make sure it's nothing serious. They will likely put a needle in the mass and see what type of material is present inside, and this will lead their treatment plan.

This doesn't present like a bee sting.

Best of luck with your boy!
1Pet Parents found this answer helpful

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