Itchy, watery eyes and a stuffy nose? Smells like seasonal allergies. About a quarter of U.S. adults deal with seasonal allergic rhinitis, or hay fever. The immune system reacts to the airborne pollen ...

Hay fever affects roughly one in four UK adults. Symptoms are caused by three different types of pollen: tree, grass and weed pollen. As hay fever season typically runs from March to September, this ...

Pollen is already ramping up in parts of the South and West. Here’s when tree, grass and weed pollen will spike — and which regions will have the highest levels this year.