Asthma
Controlling Asthma Triggers See All Allergens: Pollen in Controlling Asthma Triggers Pollen is the most common cause of hay fever. Read on for more information--and helpful tips for reducing the effects of hay fever during pollen season. ...more Allergens: Animals in Controlling Asthma Triggers Household pets, such as cats and dogs, are the most common sources of animal allergens. Here's what you need to know to about symptoms and treatments.