Remember asking your parents relentlessly for a kitten when you were growing up and they always told you no because they were allergic to cats? Years later you suspected they may have been fibbing, but they may have been telling you the truth, as well. Many people are affected by pet allergies.
People with pet allergies have reactions when they are exposed to proteins, or allergens, in animals' saliva, dander or urine. The reaction is caused by the immune system responding to the proteins as they are carried through the air and come into contact with the respiratory tract. The affected person will experience symptoms like a runny nose or sneezing in mild cases, while someone who is severely allergic will experience more pain, shortness of breath, wheezing or difficulty sleeping. For people with mild cases, the symptoms may be consistent with those of the common cold, but if they persist for more than one week, they should call a doctor. When people who have severe allergies come into contact with an animal and symptoms flare up, they should seek emergency care.
According to mayoclinic.com, people are "more likely to develop sensitivity to pet allergens if pet allergies or asthma runs in [their] family… A number of studies suggest that exposure to cats in early childhood may slightly decrease the risk of cat allergy. Other studies suggest that early exposure to dogs has no effect on risk or only slightly increases the risk."
Advanced complications caused by pet allergies can include sinus infections like sinusitis. People with asthma and pet allergies may be at risk of severe asthma attacks requiring emergency medical treatment.
If you have pet allergies there is little you can do to prevent them from causing complications besides getting rid of your pets. While some breeds are touted as "hypoallergenic" and many people think shorthaired animals cause fewer allergic reactions than longer haired pets, it's animal dander (skin scales) that causes allergic reactions – not hair. However, some breeds do produce less dander than other breeds, including poodles and schnauzers.
If you can't give you up your pet, try using allergy reduction products, limit your pets to as few rooms in your home as possible and ban them from your bedroom, use a HEPA filter on your heating/air conditioning unit, use a vacuum with a HEPA filter, frequently clean the walls of your home, wash your pets often and do not place litter boxes near air vents.