The UK's Most Common Allergy

If you have asthma, hay fever can worsen asthma symptoms - so take your "preventer' inhaler regularly

- Dr Sarah Jarvis

New research from William Russell Insurance shows that the most common internet search for allergies are to penicillin, dogs, cats, pollen and latex. Allergies happen when your body's immune system which normally helps you fight off invaders like germs - identifies something (pollen, penicillin, a food etc) as an enemy and attacks it. Your immune system makes proteins called antibodies, which recognises that substance next time it encounters it and puts your immune system on high alert.

There are different types of allergic reaction. The most dangerous is an "immediate IgE" reaction which comes on very rapidly and can lead to anaphylaxis: swelling of the lips, tongue or throat, shortness of breath, lightheadedness, itchy rash, rapid heart rate and collapse. This is a medical emergency. If you have ever had an anaphylactic reaction, you should be referred to an allergy clinic for tests.