Many experts are still trying to understand what causes allergies and why rates are on the rise. Sense about Science say that researchers now believe a whole range of environmental and lifestyle factors have acted to together to reduce our exposure to a range of microbes, which prevent the immune system from overreacting to harmless substances.

Contrary to popular belief, you won't suffer from allergies if you were exposed to fewer germs as a kid. This 'hygiene hypothesis' simply isn't true, according Allergy specialist Dr Michael John Radcliffe from the BMI Sarum Road Hospital in Winchester. Instead, he cites four other possible reasons for those allergies:

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1. Antibiotics

Using antibiotics
reduces the diversity and frequency of the bacteria on your skin and in
your gut, making it more difficult for your immune system to function
normally and distinguish harmful bacteria from the harmless. Excessive
antibiotic use could account for part of the increased incidence of

2. Genetics

Some children are more genetically predisposed to get an allergy, especially if parents or siblings have the same allergy.

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3. Childhood diet

There is some evidence that the foods you are exposed to as a child can determine whether you have an allergy when you are older.
It is thought introduction to common allergenic foods may prevent you
from developing an allergy to that food. As parents are more fearful of
allergies they exclude common allergens from their child's diet and as a
result the child has a higher risk of becoming allergic.

4. Environment

Current research
shows that the allergy genes may be 'switched on' or 'switched off' by
external environmental factors, such as viral infections.

What is an allergy?

Radcliffe explains that an allergic reaction occurs when your immune
system responds to something that would ordinarily be a harmless. For
the majority of people these materials cause no problem at all, but in
those who are allergenic their immune system identifies the substance as a 'threat' and subsequently produces an inappropriate reaction.
After contact with an allergen, the immune system has an antibody
response and releases a substance called histamine - the chemical that
causes the irritating, uncomfortable symptoms associated with allergies.

How do you know if you've developed an adult allergy?

An allergy isn't always obvious.
Typical allergy symptoms include sneezing, an itchy, runny or blocked
nose, itchy, red or watering eyes, wheezing, a tight chest, shortness of
breath, coughing, a raised and itchy rash, swollen lips, tongue or
face, tummy pain, sickness or dry, red and cracked skin.

of anaphylaxis (severe allergic reactions) might include flushing of the
skin, hives, a sense of impending doom, swelling of the throat and
mouth, difficulty swallowing or speaking, alterations in heart rate,
severe asthma, abdominal pain, nausea and vomiting, a sudden feeling of
weakness (drop in blood pressure) and unconsciousness.

What should you do?

1. Keep a record

Keep a record of timings, symptoms and allergens so
you have a clear story to present to your GP. Sense About Science say
most doctors would rule out an allergy if a person doesn't have a
documented record of a response to an allergy where a skin prick or blood test were negative.

2. See your GP

Unfortunately, there isn't one test to diagnose all allergies, so be wary of allergy tests sold on the high street and online, such as applied kinesiology or hair testing. Being diagnosed with an allergy requires speaking to a doctor and undergoing medical tests (usually a skin prick or blood test), so you should see a GP immediately. 

3. Never self-diagnose

According to Sense About Science, if allergies are on the increase, so are confusions about what is and isn't an allergy. Fears about food allergies are leading people to follow unnecessarily restrictive diets.

4. Get allergy savvy

If you have a severe allergy, ask the doctor to help you formulate a management plan in order to minimise exposure to trigger allergens and devise medicine options, if necessary. 

5. Do your research

There is also such a thing as a cross-reactive allergy. For example, a birch pollen
allergy may mean you have a reaction to kiwi fruit, apples, pears,
peaches, plums coriander, fennel, parsley, celery, cherries, carrots,
hazelnuts and almonds. Grass pollen could mean peaches, celery, tomatoes, melons and oranges are also triggers. And natural rubber latex allergy
could rule out bananas, avocados, kiwifruit, chestnut and papaya,
because the proteins in these foods are the same shape as those in
latex. It doesn't mean you have more than one allergy, but a single one triggered by different things.

What do you think?