Why Does My Dog Have Hives? A Quick Guide from KyMobilePetGrooming

As a mobile pet groomer, I see all kinds of skin issues—from dry patches to full-on allergic reactions. One that surprises pet parents the most? Hives. Yep, just like humans, dogs can break out in itchy, raised bumps called urticaria, and it often shows up without warning.

Recently, I had a Great Dane client come down with hives, and it got me thinking—this is something more pet owners should know about.

What Are Hives?

Hives are small, round welts that pop up on your dog’s skin. They’re usually itchy, red, and can appear anywhere—but are most often seen on the face, belly, or legs. In short-haired dogs like Great Danes, they’re super easy to spot.

Common Causes of Hives in Dogs

Here are some of the most frequent culprits I’ve seen in my grooming experience:

1. Allergic Reactions

This is the #1 cause.

Insect bites or stings (bees, ants, spiders, etc.) Vaccines or medications (even flea/tick treatments) New foods or treats (common allergens include chicken, beef, or grains) Pollen, mold, or dust (especially during allergy season) Shampoos or topical products not meant for pets

2. Contact Irritants

Dogs can react to:

Freshly treated grass or lawns Cleaning chemicals New laundry detergents (used on dog beds or blankets) Plastic or synthetic fabrics

3. Stress or Anxiety

Dogs can manifest emotional stress physically. Loud noises, new environments, grooming anxiety, or even separation can be triggers.

4. Underlying Health Issues

Though less common, hives can sometimes be linked to autoimmune conditions or other internal imbalances. That’s where your vet comes in.

What You Can Do (and When to Call the Vet)

For Mild Hives:

Cool bath with oatmeal or gentle, fragrance-free shampoo Benadryl (Diphenhydramine): Often safe and effective. The general rule is 1 mg per pound of body weight every 8–12 hours. Example: A 120-lb Great Dane could take 120 mg (typically 3 adult tablets)—but always double-check with your vet first.

Avoid the Trigger:

Try to recall any recent changes in:

Food or treats Medications Environment (freshly sprayed lawns, new bedding, etc.)

Emergency Signs – Act Fast!

If your dog shows any of these, go to the vet immediately:

Swelling around the eyes, muzzle, or throat Vomiting or diarrhea Trouble breathing or collapse

Final Thoughts from KyMobilePetGrooming

Big dogs like Great Danes may seem tough, but their skin can be surprisingly sensitive. If you ever notice hives on your pup, don’t panic—it’s usually treatable and often preventable once the trigger is identified.

As always, if you’re unsure or worried, reach out to your vet—and feel free to message me for a second opinion on shampoos or grooming-related triggers.

Stay safe and give your pup some extra love today!

— Ky, Owner & Groomer at KyMobilePetGrooming