Dog Allergy Symptoms
Updated 27 March 2026
Food allergies in dogs are often misdiagnosed because they share symptoms with environmental allergies, parasites, and skin conditions. Understanding which signs point specifically to diet is the first step toward finding relief for your dog.
Key difference: timing
Environmental allergies (pollen, grass, dust mites) are typically seasonal and improve during certain times of year. Food allergies are perennial and persist regardless of season. If your dog itches just as badly in winter as in summer, diet is worth investigating.
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Skin and Coat Symptoms
- ✓Constant itching, especially around the face, ears, paws, and groin
- ✓Red, inflamed, or thickened skin
- ✓Hair loss or bald patches from excessive scratching
- ✓Recurring hot spots that do not fully resolve
- ✓Hives or raised welts shortly after eating
- ✓Dull, dry, or flaky coat despite regular grooming
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Ears Symptoms
- ✓Recurring ear infections (bacterial or yeast)
- ✓Dark, waxy discharge from ear canals
- ✓Head shaking and ear scratching
- ✓Redness and odour from within the ear
- ✓Thickened or crusty ear flaps
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Gastrointestinal Symptoms
- ✓Vomiting, particularly 1 to 2 hours after eating
- ✓Loose stools or diarrhea that persists beyond a week
- ✓Flatulence more frequent than usual
- ✓Gurgling stomach sounds (borborygmus)
- ✓Increased frequency of bowel movements (3 or more per day)
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Behavioural Symptoms
- ✓Restlessness and inability to settle due to itching
- ✓Rubbing face on carpet or furniture
- ✓Licking paws excessively, especially after meals
- ✓Reduced appetite or selective eating
- ✓Increased irritability or mood changes
When to See a Vet
While dietary changes can help with suspected food allergies, professional diagnosis matters. See a vet promptly if your dog shows:
- ⚠Open sores, oozing wounds, or signs of secondary infection
- ⚠Swelling around the face, muzzle, or throat (potential anaphylaxis)
- ⚠Sudden and severe vomiting or diarrhea
- ⚠Significant weight loss over a short period
- ⚠Symptoms that do not improve after 8 weeks on a strict elimination diet