The Met Office has issued a rare'red alert' for hay fever sufferers due to high pollen levels in England and Wales, with Scotland and Northern Ireland also experiencing similar levels. The warning comes as a result of a high pollen count, which is expected to drop towards the end of the week. Hay fever, the most common name for pollen allergy, is most commonly caused by grass pollens. Symptoms include an irritated throat, eyes, nose, and inner ear feeling itchy, sweating, headaches, facial pain or reduced sense of smell. According to NHS data, around 20% of the population in the UK deals with hay fever, affecting around 13 million people. There are numerous treatment options available, including over-the-counter daily antihistamine tablets or nasal sprays.