Spot it -- itchy skin or gastrointestinal issues are typical symptoms. Since itchy skin can also appear with environmental allergies, your vet may want to adjust your pet's diet (limiting it to specific ingredients for a trial period of a month or more, for example) to help make the diagnosis. "If the animal does have a food allergy, its itching will recur when the old food is reintroduced," says William H. Miller Jr., VMD, professor of dermatology at the Cornell University College of Veterinary Medicine.
Treat it -- Once an allergy is confirmed, "dietary modifications are the only way to treat the condition," says Miller.
Environmental-Including pollens, mold spores and dust mites
Spot it -- itchy skin is common, but respiratory issues can also be a red flag, with the occasional runny eyes and sneezing in dogs and asthma in cats. If Fluffy's symptoms are seasonal, that's a sign that it's something in the air. "If not, we need to exclude a food allergy first to arrive at a diagnosis of environmental allergy," says Cain. A dust mite allergy could cause year round symptoms.
Treat it -- Many vets typically start with simple meds, like antihistamines, to tame the symptoms. But beware. "These drugs may become ineffective as the animal's allergies worsen," which can happen if, for example, the amount of the allergen in the air increases from season to season, explains Miller. Immunotherapy shots or drops may be an option for long-term relief. You could also try reducing your pet's exposure to the allergen vacuuming regularly, or wiping down paws or taking baths after walks outside.
Spot it -- have fleas will make any pup itchy, but add an allergy and you're looking at a whole additional layer of misery. "With a flea allergy, there is an accentuated allergic response to even a low number of flea bites, due to the exposure to flea saliva, which triggers the allergic reaction," explains Cain. Signs of a flea allergy? "Dogs are usually itchy around their tail base or the back part of their body near the butt, inner thighs, and groin areas," says Cain. Other symptoms include excessive licking, chewing, hair lose, and red or crusty skin.
Treat it -- The solution is to eliminate the infestation. Stick with the strict flea-control treatment recommended by your vet.