How do you get allergies, like peanut allergies?

My brother has a peanut allergy, and he can't eat them or else he dies. ((not even kidding you)).

We did some research and no one else im my family ever had a peanut allergy!!!!!!!!! so how did he get it?

Can you leave me a URL???

THNX

The tendencies to develop allergies are normally inherited, but over exposure to certain foods, environmental substances etc. can also lead to getting a particular allergy.
As a visual - if you have a big bucket that a drop of water falls into, the drop of water isn't really noticable, till you have so many drops that your bucket overflows. To apply this to allergies, you can be exposed to a certain substance in small quantities and you will feel no effects, till something accumulates in your body and your antibodies go in attack mode.



http://www.webmd.com/allergies/tc/food-a...
Food allergies occur when the body's immune system overreacts to substances in food you have eaten, triggering an allergic reaction. Food allergies are more common in young children than in adults. This may be because children's immune and digestive systems are not completely developed.2

Eggs, milk, peanuts, wheat, soy, and fish cause most of the allergic reactions in children. Some babies are so sensitive to these foods that if the offending food is eaten by the mother, drinking her breast milk can cause a reaction. Most children outgrow allergies to milk, wheat, eggs, and soy between ages 3 and 5. Children rarely outgrow an allergy to peanuts or fish.
Peanuts, tree nuts (such as walnuts or almonds), fish, and shellfish cause most of the allergic reactions in teens and adults. Adults generally remain allergic to the food for life.
Food allergies are most common in people who are atopic, meaning they have an inherited tendency to develop allergic conditions. These people are more likely to have asthma, various allergies, and a skin condition called atopic dermatitis.

If you are highly sensitive to a particular food, you may have an allergic reaction by simply being near the food. Flying in airplanes where other passengers are eating peanuts or simply eating in a seafood restaurant may cause symptoms.

The more common a food is, the more likely it is that people will be allergic to it. For example, rice allergy is seen in Japan, and codfish allergy is seen in Scandinavia. As foods from around the world have become more available, the number of allergic reactions to exotic fruits such as kiwi and papaya and to seeds such as sesame seeds and poppy seeds have increased.

Because peanuts are used in so many foods, peanut allergy has increased in the United States in the past two decades and is now a major cause of severe allergic food reactions. Peanut allergy is usually lifelong and tends to become more severe over time. For more information, see the topic Peanut Allergy.

Celiac disease is caused by an allergy to a protein (gluten) found in wheat and some other grains. For more information, see the topic Celiac Disease.

Cross-reactivity
Many people are allergic to foods that are similar or somehow related. This is called cross-reactivity. For example, if you are allergic to shrimp, you may also be allergic to other shellfish, like crab or lobster. If you are allergic to peanuts, you may be allergic to other members of the legume family, such as peas and beans.

Oral allergy syndrome is a type of cross-reactivity. In this syndrome, people who have pollen allergies (such as a grass allergy) may develop itching, redness, and swelling of the lips and mouth when they eat fruits or vegetables that contain a protein that reacts with the pollen. These symptoms usually resolve quickly and do not involve other body parts.

A growing number of people, especially health care workers, are discovering they have an allergy to latex. Latex is the natural sap of the rubber tree. It is used in making surgical gloves, condoms, balloons, and other products. If you have a latex allergy, you may also have allergies to kiwis, passion fruit, papayas, bananas, avocados, figs, peaches, nectarines, plums, tomatoes, celery, and chestnuts.

thx for the advice i no its a dumb thing for me to ask but....
and ur just born with allergies its not a family thing its just how ur body reacts to different things

Some people just get born with allergies. I'm allergic to a bunch of foods and even more plants (mostly trees) and no one else in my family is that allergic.

You can also become allergic to something. For instance, hospitals are having a real problem with their doctors and nurses becoming allergic to latex because they use latex gloves so much.

your born with it

It's possible that he just developed it. I know a little girl who is so allergic to seafood, just the smell (I kid you not) of certain seafoods: crab, crawdads, shrimp, will make her eyes and throat swell and it gets to the point where she has to be taken to the hospital.

I am the only one in my family with a peanut allergy that is known. It just develops sometimes. Of course mine developed when I was 25 (I ate peanuts all the time but always kinda felt wierd only it because lifethreatening at 25.) so you aren't completely out of the woods for developing it...I'd be careful. Of course if he's deathly allergic then he shouldn't be around people eating peanuts so you're probably not eating them anyway.

Looks like that brother had a defective gene that caused his immunogloublin-E antibody---or IgE---the main "bad guy" that causes allergic reactions---to make his immune system much more sensitive to peanuts.

This means that he is also likely allergic to other tree nuts. So best for him to stay away also from legumes that are like peanuts, especially things like cashews, walnuts, pecans, and hazel nuts....for the time being.

I developed an allergy to peanuts about 10 years ago. I didn't have a problem with them until then, and I ate a lot of peanuts when I was a kid. Now I can eat a few. But if I eat any form of peanuts within 3 days of that time, my nose stops up and I have difficulty breathing. It gives me asthma like symptoms.