By Dr. James Hogg
Have you ever owned a cat? If you have, have you ever found it has brought you little presents? Like a dead bird or mouse, lovingly left on your pillow? Your cat might mean well, but you won't thank it for trying.
That's sort of like the way your body's immune system works if you have a food allergy. It's thinks it's helping you out, but it's not.
How does the immune system normally work?
Your body is protected by your immune system. It's made up of many different kinds of white blood cells. Each guards you from attack in a different way. Normally, these cells patrol every part of you, on the look out for invaders like viruses, bacteria or parasites.
All cells in your body carry antigens. These are like ID cards for each cell. The immune system checks these antigens, so it knows who belongs in the body and who doesn't.
Invaders have antigens too, but they're not right for your body. The immune system can tell they don't fit in. When a white blood cell spots an invader, it sounds the alarm.
This alarm is something called histamine. That's a chemical that makes your arteries get bigger and summons more immune cells. The new arrivals spray histamine too, creating a chain reaction and a louder alarm. Normally, this would be great! An invading germ would get surrounded by angry immune system cells. They'd wipe out the bug and the alarm would die away.
But in a food allergy, or any allergy, your immune system gets confused.
What happens in a food allergy?
Food has antigens too. In a food allergy, your immune system gets confused. It mistakes a food for an invader and overreacts. The antigen on the food triggers release histamine release and starts the immune chain going. That's an allergic reaction.
Histamine can affect your whole body. It can make your heart race and your skin break out in a bumpy rash. Your lungs may get tight, which makes it hard to breathe. Your nose and eyes can start running. It can make you throw up.
All of this might be helpful, if you were under attack by a germ. It would help flush the germ out. But it's no help at all against food.
If the histamine alarm is big enough, or goes on long enough, it can cause your body to go into shock. Shock caused by an allergy is called anaphylactic shock. Basically, your body can't keep up with the demands the alarm puts on it.
Some people are severely allergic to their trigger antigen. Even a tiny piece of food containing the antigen causes a huge overreaction. It can start very quickly, so it's important to have the right medicines handy to keep your immune system calm.
How to deal with a food allergy
For mild allergies, you can use antihistamines. You can take these as tablets. They stop the alarm going off in the first place, or calm it down if it's already going. No alarm means no allergic reaction.
For severely allergic people, antihistamines aren't enough. They need adrenaline, which quickly reverses the effects of histamine. It relaxes the lungs and shrinks your arteries back to their normal size.
That's why some people carry an Epi-pen with them. If something triggers their allergy, it contains a quick injection of adrenaline. Adrenaline is called Epinephrine in America, where the first Epi-pens were made. Many other brand names of adrenaline pens exist now, but people often refer to them all as Epi-pens.
The best way of avoiding the allergic reaction is to avoid the antigen. Usually, you won't know you have a food allergy until the first time it happens. But after that, doctors can run tests to see exactly what triggers your attacks.
Once you know what your trigger is, you must avoid it. It's vital you don't eat any food containing the trigger. Let your friends and family know, so they can help you. Wear a medi-bracelet. That's a bracelet with information written on it about what you're allergic to.
Somewhere between 2-5% of people have some kind of food allergy. The most common ones are peanuts, shellfish, soy, other nuts, milk, eggs, wheat and fish. The allergies you have when you're young often disappear as you get older. But adults can sometimes develop a new allergy later in life.
All this can make allergies seem frightening. And it can be a real pain to have to check your food all the time. But it can save your life!
Once you know about your allergy, there's nothing to stop you eating out, or enjoying your food, as long as you're careful.
Here Are Some Tips:
- ALWAYS wear your medi-bracelet
- ALWAYS tell people about your allergy
- ALWAYS carry your Epi-pen
- ALWAYS know what is in your food
If you have food allergies, follow these simple steps when eating out to avoid an allergic reaction.
- Tell the waiter you have a food allergy
- Talk to the waiter to help you choose something without the trigger food
- If the restaurant serves the trigger food explain to the waiter or chef your food needs to be made separately
- If you have severe allergies request your plate be bought out individually
Dr. James Hogg is one of the team of medical writers working for Medikidz, a charity that produces comic books that tell children in simple, informative terms the details of their diagnosis.