Pollen Allergy Make an Appointment Refer a Patient Ask a Question Reviewed by Sanny Chan, MD, PhD (November 01, 2016) Pollen from trees, grasses and weeds can be inhaled and cause allergy and asthma symptoms. Pollen may travel many miles in the wind, so trees, grasses and weeds beyond your immediate area can cause allergy and asthma symptoms. Pollen allergies are often seasonal, and allergy and asthma symptoms occur when the amount of pollen in the air is high. Examples of allergy symptoms include itchy eyes, runny nose and sneezing. Examples of asthma symptoms can be coughing, wheezing and difficulty breathing. These symptoms may vary depending on weather conditions and where you live. Once an allergy has been identified, your healthcare provider may recommend medications or therapies to control symptoms. The next step is to decrease or eliminate exposure to the allergen. This is called environmental control. Evidence shows that allergy and asthma symptoms may improve over time if the recommended environmental control changes are made. View Allergy Home Mold Allergy Clinical Trials For more than 100 years, National Jewish Health has been committed to finding new treatments and cures for diseases. Search our clinical trials.