Common allergies in pets can include food allergies (e.g. to ingredients like chicken, beef, or grains), environmental allergies (e.g. pollen, mold, dust mites), and flea allergies. Symptoms of allergies in pets can vary but may include itching, redness, hair loss, ear infections, and gastrointestinal issues. It's important to consult with a veterinarian if you suspect your pet has allergies to determine the best course of action for treatment.