What should I check if my dog has hives and is vomiting? | arlo.® Atlas
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Overview
If your dog has hives and is vomiting, the main thing to check is whether this could be an allergic reaction or something else that needs prompt veterinary advice. Hives can sometimes appear after a trigger such as a bite, food, a new treat, medication, shampoo, pollen or another environmental irritant. Vomiting can happen alongside that, so it’s worth checking your dog closely rather than waiting to see if it passes.
There can be several possible causes, and you usually can’t tell the exact one from the signs alone.
Things To Check
1. Check how quickly the hives appeared and whether the vomiting started around the same time.
2. Look closely for swelling around the face, muzzle, eyelids or ears, as well as any redness, heat or raised patches.
3. Watch your dog’s breathing. Noisy, fast, laboured or changed breathing is more concerning than the hives themselves.
4. See whether your dog is bright, resting normally, or seems dull, shaky, restless or unusually unsettled.
5. Check for any recent changes such as a new food, treats, chew, medication, shampoo, lawn treatment, flea product or time in long grass.
6. Look for possible sting or bite sites, especially on the muzzle, paws, belly and around the face.
7. Note how many times your dog has vomited, whether they can keep water down, and whether there is diarrhoea as well.
Common Causes
The most common cause is an allergic or sensitivity reaction, which may be triggered by something eaten, touched or bitten. Insect stings and bites can also bring on hives, and some dogs react to new shampoos, topical products or environmental allergens.
Less commonly, vomiting and hives may happen with a stronger systemic reaction, which is one reason to keep a close eye on breathing, swelling and your dog’s general behaviour.
What To Do
Stay calm and keep your dog somewhere cool and quiet so you can monitor them properly. Remove any obvious possible trigger if you can do so safely, such as stopping a recent new treat or moving them away from the area where the reaction seemed to start.
Keep checking their breathing, swelling and alertness over the next short while. If the hives are spreading, the vomiting continues, or your dog seems less well, don’t wait to see if it clears on its own.
It can help to note the time the signs started, what your dog ate or came into contact with, and whether anything changed before the hives appeared. That information is useful if you need to speak to a vet.
When To Contact A Vet
Contact a vet promptly if your dog has hives and vomiting together, especially if the signs started suddenly or are getting worse. Seek urgent advice straight away if there is facial swelling, pale gums, collapse, repeated vomiting, marked lethargy, or any breathing change.
If the reaction is mild and settles quickly, it still makes sense to speak to your vet for advice about possible triggers and what to watch for next.
Related Questions
What can cause sudden hives in dogs?
Are hives in dogs always an allergy?
What should I do if my dog swells up after a bite or sting?
Atlas is here to support owners with practical, easy-to-understand guidance. It is not a substitute for professional veterinary advice. If you're concerned about your animal's health, symptoms worsen, or something doesn't feel right, contact your vet.