Updated September 25, 2026. Fact-checked against veterinary sources; review by a licensed veterinarian is in progress. See our editorial policy.
Quick answer: Environmental allergies in dogs typically start between 6 months and 3 years of age, and food allergies can appear at any age, including in young dogs. But itching in puppies is often caused by other things first: fleas, mange mites, ringworm, or skin infections. A vet can check for these before diagnosing allergies.
Common causes of itching in puppies
- Fleas
- Sarcoptic mange: intensely itchy, contagious, often affects ear edges and elbows
- Demodex mites: patchy hair loss, often not itchy at first
- Ringworm: a fungal infection, contagious to people
- Puppy pyoderma: small bumps and pustules on the belly
- Early allergies
Signs allergies may be starting
- Paw licking, face rubbing, and ear infections
- Seasonal patterns
- Itching that persists after parasites are ruled out
What helps
- Strict flea prevention
- A vet exam with skin scrapings and other tests
- A food trial if food allergy is suspected
- Early management to prevent chronic skin changes
Sources
- Olivry T, et al. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015
- Merck Veterinary Manual: Atopic dermatitis in dogs
- Merck Veterinary Manual: Flea allergy dermatitis
- Merck Veterinary Manual: Mange in dogs
This article is for general education and is not a substitute for care from your own veterinarian. Learn about The Pet Vet and our editorial policy.