Allergies are caused by overly sensitive immune systems. When your body comes in contact with a certain substance that's generally considered harmless, it overreacts and sends out a team of chemicals to fight the invading allergen. One of these chemicals is histamine, which is what causes cold-like allergy symptoms, including sneezing, itchy eyes and runny nose. When it comes to pet allergies, your body is most likely reacting to the proteins in the animal's saliva and sebaceous glands, as well as to the animal's dander, or shed skin flakes. While there's no cure for pet allergies, there are some relatively effective treatments.
First and foremost, doctors recommend avoidance as the most effective treatment. If you're allergic to pets, don't have any in your house and try to stay away from homes with animals. But if that's impossible, some over-the-counter medications have proven to help control most allergy symptoms. Antihistamines are available with or without prescription, and they are come in pill form and nasal sprays. Similarly, decongestants can be prescribed by a doctor or purchased over the counter. Certain asthma medications help with pet allergies, too, particularly prescription steroids.
The other common way to treat pet allergies is through immunotherapy, or allergy shots. The process takes a long time, beginning with a shot or two every week and gradually reducing to one shot per month. Each immunization consists of a dosage of the allergen that you have trouble with; the idea is to gradually get your body used to pets so that you can be around them without any allergic reactions. Immunotherapy treats the actual allergy, as opposed to allergic symptoms. However, immunotherapy is expensive and time-consuming, and it doesn't work for everyone. Still, it's considered safe, and it could drastically improve your quality of life.