Allergies occur as a reaction to allergens, environmental substances which elicit reactions that are acquired, rapid, and predictable. There are many types of allergies, and each one has a different trigger. Animals with fur or feathers, for example, can easily trigger allergies in children. Studies show that among pets, cats cause more severe allergic reactions, with male cats generally producing more allergens than their female counterparts. Experts say that when it comes to pets, the problem is not with the hair. It is actually the dander, or the microscopic scales of dead skin which pets constantly shed. This section tackles allergies, their causes, their symptoms, possible cures, and any other topic relating to allergies.