The amount of grapes needed to cause poisoning in dogs can vary from dog to dog. A larger dog may ingest a certain number of grapes and only experience mild symptoms, a small dog could eat the same amount and face more serious consequences.
Brutlag A: Grape, Raisin and Currant Poisoning in Dogs. VCA Hospitals.
Dog Food Allergies vs Dog Food Intolerances. In a true dog food allergy, the culprit is often a food protein that triggers an adverse immune response, which then causes cells in the body to release histamines or compounds that lead to itching and many other allergic signs.

Does your dog have allergies? Find out what symptoms of allergies in dogs to look for, the most common causes of dog allergies, and the most effective allergy treatment for dogs.
Causes of Dog Allergies. You may have heard that some dog breeds trigger allergy symptoms while others don't, or that short-haired dogs are safe while long-haired dogs prone to shedding are not.

Understanding Grape Toxicity in Dogs. Symptoms of Grape Poisoning. What to Do If Your Dog Eats Grapes. Prevention Strategies.
Dogs allergies can cause severe symptoms, including swelling and itching around the nose and eyes, a rash on the face and neck, and coughing.What are the symptoms of dog allergies? Symptoms of a dog allergy may range from mild to severe. They may include