What doctors call rhinitis (rhine-I-tis), most people call hay fever. This condition may occur in both adults and children and can be caused by many different factors. Substances such as dust mites, pet dander, mold spores, and pollen are some of the main allergens leading to hay fever. Symptoms include a stuffy, runny nose; itchy, watery eyes; sneezing; and sometimes a headache. Because a child must first be exposed to an allergen, it's not uncommon for allergies to appear suddenly at any age. The tendency toward allergies and hay fever runs in families. Treatment usually focuses on easing the symptoms and avoiding the source of the reaction. Not all medications are appropriate for children, so talk to a healthcare provider about how to avoid and treat childhood allergies.