Allergic inflammation immediate allergic reaction or as a Type I allergic reaction. The reaction is caused by the release of histamine and mast cell granule proteins by a process called degranulation, as well as the production of leukotrienes, prostaglandins and cytokines, by mast cells following the cross-linking of allergen specific IgE molecules bound to mast cell FcεRI receptors. These mediators affect nerve cells causing itching, smooth muscle cells causing contraction (leading to the airway narrowing seen in allergic asthma), goblet cells causing mucus production, and endothelial cells causing vasodilatation and edema. The late phase of a Type 1 reaction (which develops 8–12
Pollen count Pollen count Pollen count is the measurement of the number of grains of pollen in a cubic meter of air. High pollen counts can sometimes lead to increased rates of an allergic reaction for those with allergic disorders. Usually, the counts are announced for specific plants such as grass, ash, or olive. These are tailored to common plants in the measured areas. Mild winters with warmer days lead to an increase in pollen counts while colder winters lead to delayed pollen release. In the UK, the public announcement of the pollen count was popularised by Dr. William Frankland, an immunologist.