Pollen allergy (also known as allergic rhinitisAllergic rhinitis (or Rhinitis allergica, or hay fever) is an inflammation of the nose occuring when the immune system overreacts to allergens (e.g., pollen) in the air. or hay fever) is one of the most common forms of allergy in the US, with approximately 10 to 30 percent of adults and as many as 40 percent of children affected. Typically, symptoms of hay fever include nasal congestion and obstruction, sneezing fits, conjunctivitis, ear infections as well as allergic asthma. It is a regionally variable disease and heavily influenced by several environmental factors, most importantly the local flora, weather, climate, and severity of air pollution.

So what’s causing hay fever symptoms in the US? It depends on the season. In springtime, tree pollen are the most common allergen sources triggering hay fever in the US – for example Alder, Ash, Aspen, Beech, and Birch. In Fall, weed pollen like Burning bush, Cocklebur, Lamb’s-quarters, Mugwort, and Pigweed are in their peak season.