A surge in pollen levels this weekend means the hay fever season is now in full swing — with up to 13 million people set to be affected by debilitating symptoms. Also known as allergic rhinitis, hay fever us caused by the body’s reaction to airborne pollen, typically from trees, grasses and weeds.

The most common symptoms include sneezing and coughing, a runny or blocked nose and itchy, red or watery eyes. Some sufferers may also experience an itchy throat, mouth, nose or ears, loss of smell, headache and tiredness. While the symptoms can be similar to a cold, hay fever is more likely to cause itchy eyes and skin irritation and less likely to trigger body aches or a fever.

The effects of hay fever are usually worst between March and September, particularly when the weather is warm, humid and windy.

The Met Office pollen forecast is updated daily and can give an indication of how bad symptoms might be over the coming five days.

Experts have predicted a “more severe” season this year, due to warmer weather last June when pollen was forming in tree buds.

Simple steps can help to reduce the impact of hay fever. These include taking a daily antihistamine and putting petroleum jelly around your nostrils to trap pollen.

Other ways to reduce exposure include wearing wraparound sunglasses, a wide-brimmed hat, and keeping windows closed on high-pollen days.

Showering and changing clothes after you have been outside can also help get rid of any lingering pollen particles.

Pharmacists can provide advice about the best antihistamine tablets, drops or nasal sprays.

In more severe cases, your GP may be able to prescribe a steroid treatment or immunotherapy, which helps build tolerance to pollen.

Research has suggested that eating foods such as onions, apples, broccoli, grapes and tomatoes — which are rich in an antioxidant called quercetin — may help.