SUMMER SNEEZE

Nearly half of us experience allergies at some point in our lives and one in two think we suffer from them, but haven’t been diagnosed.

Despite how common they are, there’s much confusion around allergies. What are they, how do they develop and – most importantly – how can we avoid illness or emergencies as a result of them?

Allergy myths – busted

'Once you've had an allergic reaction, exposure to the same allergen will be much worse'

This is a myth. Many factors influence the severity of a reaction, including the length of time since the last exposure and the degree of exposure. That said, if you've been told you are allergic to a food or a drug, you must not try it again until a specialist has excluded an allergy.

'You can avoid pet allergies by getting hypoallergenic cat and dog breeds'

Unfortunately, there's no such thing as a truly hypoallergenic animal. Certain breeds may shed less hair, but all dogs and cats produce allergenic proteins from saliva, skin and sebaceous glands.

‘Honey Cures Hayfever'

Sadly not. Bees make honey using pollen from flowers, not the pollen in weeds, grasses and trees that trigger hayfever.

What is an allergy?

It’s when your immune system – your body’s defence – is overreacting and treating a harmless substance as a threat, leading to symptoms such as rashes and swelling. With food allergies, the most common in adults are peanuts, tree nuts, seeded and stoned fruit, and shellfish, while in children, eggs, cow’s milk and peanuts dominate.

Are allergies more likely to develop in some people than others?

The UK has one of the highest allergy rates in the world, although it’s not understood exactly why. Genes play an important part; if you have one parent with an allergy, you have a 30-50% chance of developing one, and this rises to 60-80% if both parents have allergies. But it’s more complicated than that. We suspect that bacteria in your gut have an influence over whether or not you develop an allergy. Events in early childhood, such as being born by caesarean section or requiring multiple courses of antibiotics, may influence the balance of gut bacteria, tipping susceptible infants into allergy. However, early exposure to bacteria appears to reduce chance of allergy, so younger siblings are less likely to get hayfever or eczema because they encounter more germs, and babies that share a home with a dog are less likely to develop a food allergy.

How can hayfever be kept under control?

Pollen allergy affects around 26% a reaction, including the length of UK adults, resulting in seasonal of time since the last exposure allergic rhinitis (or hayfever). Symptoms include an itchy nose, eyes and throat, It can also affect mental health; one US study suggested that sufferers are 40% more likely to develop depression, while a study of 1,800 UK teenagers found those with allergic rhinitis were 40% more likely to drop a grade between mocks and final exams. The correct treatment can help more than 95% of sufferers.

Simple ways to reduce pollen exposure include wearing a face mask and not hanging washing outside, as pollen will stick to it. Antihistamine cetirizine is usually recommended as it is effective, acts quickly, and is long lasting, however if this doesn’t work try to use an anti-inflammatory nasal steroid spray – but it can take time to kick in, so it is suggested to start a fortnight before pollen season.

Can

you develop allergies in later life?

You can develop one at any time.

Food allergies, hayfever and allergic asthma tend to develop earlier, while reactions to wasp or bee stings and medicines are more common in later life. If you develop one allergy in childhood, you’ll often develop another along the way.

Do at-home allergy tests work?

No! At-home allergy blood tests don’t give clear ‘yes or no’ answers like a pregnancy test and need to be interpreted by allergy experts. If you have rhinitis, asthma, a rash or swelling, speak to your GP, who can refer you to an allergy clinic in severe cases.

Can you tell the difference between an intolerance and an allergy?

Food intolerance refers to a food triggering a digestive problem, rather than allergy symptoms. For example, a common intolerance is to the milk-sugar lactose, which occurs if you don’t have enough of the enzyme lactase in the gut to digest cow’s milk, therefore causing upset stomach, diarrhoea and bloating. Food intolerance can be unpleasant, but it’s rarely dangerous. In contrast, food allergies cause the body’s immune system to be activated and can be dangerous, potentially causing anaphylaxis: the allergic reaction at the severe end of the spectrum, when either someone’s breathing is affected or their blood pressure has dropped, or both. Symptoms of low blood pressure include feeling dizzy, lightheaded, clammy, or faint. Insect stings, latex and medicines can also cause anaphylaxis.