Spring allergy season in Indiana has begun, with high pollen counts expected throughout the week. Experts suggest staying indoors during peak pollen times and using high-efficiency air filters to reduce symptoms. According to the American College of Allergy, Asthma and Immunology, allergies begin in February and last until early summer. Tree pollen is the first culprit to cause symptoms, followed by grass pollination later in the spring and summer. A mild winter like this year's weather can cause plants to pollinate sooner and a rainy spring can increase mold and allergy symptoms. The most common cause of allergy symptoms is dust mites, which can be eliminated using these steps.