What does a dog allergy look like?

Dog allergies are acute or chronic. Acute appears fast after food or drug: facial swelling, limb edema, itchy skin, hives, even breathing difficulty, shock, death.

Chronic shows digestive and skin signs: vomiting, diarrhea, itching, hives, hair loss, sometimes chronic ear inflammation. Mild cases self-heal after removing the source; severe needs a vet.