Dog allergies: signs to watch and what to do next

• Note where and when symptoms happen; photos can help show changes.
• Ask your vet about parasite prevention and checks for skin or ear infection.
• Do a food elimination trial only with a veterinary plan; allergy blood tests do not diagnose food allergy.
• Sudden collapse, trouble breathing, or rapidly developing severe signs need emergency veterinary care.

• Scratching, rubbing, chewing, or licking the skin or paws more than usual
• Red skin, hair loss, sores, or repeated skin problems
• Head shaking, ear discomfort, or recurring ear problems
• Sometimes vomiting or diarrhea alongside skin signs

Itching is a sign, not a diagnosis. An itchy dog may have parasites, infection, or another condition even if allergies seem likely. Contact your veterinarian when signs persist, recur, or disrupt sleep or normal activity.

More than one problem can be present at once. A food allergy is different from eating a toxic food. See the separate foods-dogs-cannot-eat guide for poisoning and household hazards.

• When signs started and whether they come and go
• The affected body areas, severity, and photos of visible changes
• Current food, treats, flavored medicines, supplements, and recent changes
• Flea and tick prevention used and the last dose date
• Recent baths, shampoos, cleaners, bedding, travel, or outdoor exposures
• Any vomiting, diarrhea, ear discharge, or change in appetite or energy

Bring this record, the food packaging, and any treatment history to your vet. The take-home sheet includes a short tracker you can write on.

The veterinarian starts with history and an examination. Depending on the signs, they may check skin or ear samples, assess parasites, and treat infection or inflammation while following the response over time.

If food allergy is suspected, the vet may prescribe a strict elimination diet for several weeks and then a controlled challenge with the previous food. Treats, table scraps, and flavored products can invalidate the trial, so ask exactly what is permitted. Do not start a restrictive diet for a growing puppy without veterinary guidance.

Skin or blood allergy tests may help select environmental allergens for immunotherapy after other causes have been assessed. They are not a stand-alone way to diagnose food allergy.

Follow the individualized plan for parasite control, skin or ear care, diet, medication, and rechecks. Record what improves and what flares. Some dogs need long-term management and adjustments rather than a single cure.

Ask before giving human antihistamines, creams, or other medicines. Products and doses can be inappropriate for a dog, and treatment may hide signs your vet needs to assess.

• Does itching mean my dog has a food allergy? No. Fleas, infection, other parasites, and environmental allergies can also cause itching. Your vet can work through the causes.
• Will an allergy blood test tell me which food to avoid? No. Food allergy is investigated with a vet-directed elimination diet and food challenge. Environmental allergy testing has a different role.