My dog has hives after vaccines-allergic reaction

Allergic reactions to vaccines in dogs are uncommon but can happen. Most dogs tolerate vaccines well, but some may develop mild or more serious reactions. Here’s a breakdown:

(Common) Reactions

These usually appear within a few hours and resolve on their own:

• Lethargy (tiredness)

• Mild fever

• Soreness or swelling at the injection site

• Reduced appetite

• Temporary lumps under the skin (vet may recommend benedryl)

Moderate Reactions

May need veterinary attention if persistent:

• Vomiting

• Diarrhea

• Facial swelling (lips, eyelids, muzzle)

• Hives or itchy bumps on the skin

Severe (Rare, Emergency) Reactions – Anaphylaxis

These typically happen within minutes to an hour after vaccination and require immediate veterinary care:

• Collapse or fainting

• Difficulty breathing (wheezing, gasping)

• Pale gums

• Severe swelling of face/throat

• Seizures

Risk Factors

• Small-breed dogs may be slightly more prone to reactions.

• Reactions are more likely when multiple vaccines are given at once.

• Dogs with a history of vaccine sensitivity.

What to Do if Your Dog Has a Reaction

• Mild: Monitor at home, contact your vet if symptoms worsen or don’t resolve in 24 hours.

• Moderate: Call your vet promptly for advice—may need antihistamines or anti-inflammatory medication.

• Severe: Treat as an emergency—go to the vet or emergency clinic immediately.

Prevention & Management

• Tell your vet if your dog has had a reaction before—pre-treatment with antihistamines or steroids may be recommended.

• Spacing out vaccines instead of giving several at once can reduce risk.

• Some dogs with severe past reactions may be exempt from certain vaccines, depending on laws and health risks.