Practice Notes from the AAAAI   The Journal of Allergy and Clinical Immunology: In Practice  Volume 2, Issue 6, Pages A21-A25 (November 2014) DOI: 10.1016/S2213-2198(14)00426-7 Copyright © 2014 Terms and Conditions

Great ragweed or giant ragweed pollens, like the grain identified in this photo, is known to cause hay fever. The Journal of Allergy and Clinical Immunology: In Practice 2014 2, A21-A25DOI: (10.1016/S2213-2198(14)00426-7) Copyright © 2014 Terms and Conditions

The Journal of Allergy and Clinical Immunology: In Practice 2014 2, A21-A25DOI: (10.1016/S2213-2198(14)00426-7) Copyright © 2014 Terms and Conditions