Common food allergies causing difficulties

A peanut butter and jelly sandwich or a glass of milk doesn't sound particularly threatening as a snack, but for people with food allergies, they can be deadly.

Hopkins scientists are working to study these allergies and have published two papers in the past month that may make life easier for those with the allergies.

About three percent of children in the U.S. have some type of food allergy; the most common being milk, shellfish, peanuts and eggs. This number drops for adults, with only one percent of adults having diagnosed food allergies.

According to the National Institute of Allergy and Infectious Diseases, this drop is due to the fact that many children outgrow their food allergies, especially milk allergies.

People who have food allergies are born with antibodies against molecules in certain foods. Antibodies, are typically associated with the immune response and recovering from illnesses, bind to proteins and cause the body to attack them. This is useful when a foreign substance enters the body, such as a bacteria.

If an antibody attacks molecules found in something such as peanuts, every time that person ingests peanuts, their body will launch an attack against it.

Depending on what part of the body the antibodies are released in, there can be different symptoms of a allergy, including abdominal pain, throat problems, asthma, and hives.

Many people have food intolerances, such as lactose intolerance, that are not actual allergies, doctors have a few ways of diagnosing something as specifically an allergy. The most common of these is a skin test.

According to the Food Allergy and Anaphylaxis Network, during a skin test a doctor places a drop of the allergen on a patients forearm. He then pricks the skin with a needle, allowing only a tiny drop of the suspected allergen to enter the skin. If the patient is allergic to whatever was being tested, a red bump will appear.

Since knowledge of your allergy is critical to avoiding allergic reactions, these tests may literally be lifesaving for many. A paper published last month by Hopkins allergy expert Robert Wood examined the risks, however, that these tests could have.

The idea of feeding a food, even a tiny amount, to a child who could be allergic to it is enough to make any parent queasy. Wood's paper, published in the Journal of Allergy and Clinical Immunology, was a comprehensive review of 584 completed food challenges.

Once you know that you have an allergy, the key is avoidance.

Hopkins junior Brian Harris, who has a shellfish allergy, says that he doesn't even know what would happen if he ate shellfish. "When I was little I got really sick, like all congested and wheezy, so my parents took me to the doctor and they did allergy tests and found out that I was allergic to shellfish before I had even eaten any."

Harris says that you just have to be upfront about asking restaurants if a dish contains whatever you are allergic to. "They're always nice about it. Even if a waitress doesn't know, she'll go ask someone else," he explains.

While it is often easy to tell whether something has shellfish in it, people with other allergies may have a harder time. For example, people with peanut allergies can have an allergic reaction to less than 1/1000 of a peanut. This means that they have to be particularly careful, often not even able to be in the same room as someone eating a peanut butter sandwich.

Robert Wood has co-authored a second paper this month which gives advice to people who are outgrowing their peanut allergy. People who had violent reactions to peanuts as a child most likely avoid peanut butter as they grow older, even if their allergy seems to disappear. Wood recommends otherwise.

The study, published in the Nov. issue of The Journal of Allergy and Clinical Immunology, examined 68 children who had outgrown peanut allergies. Using questionnaires and skin tests, the researchers found that three of the 68 children had relapsed into having an allergic reaction.

The surprising part of their results was that children who had eaten peanut products at least once a month since they outgrew their allergy were less likely to have their allergy come back. Based on these results, Wood and his colleagues are recommending that children who have outgrown a peanut allergy consume peanuts on a monthly basis.

Alain Joffee, Director of the Student Health and Wellness Center, says that there are at least a few Hopkins students with major food allergies every year.

Joffee points out that living with a major allergy "can have a huge impact on a student's life since they must always be on guard and vigilant about what they eat. Even going to a simple social function like a birthday party can be a problem if ice cream sundaes, including peanuts, are being served."

He says that the best way for a student to deal with a food allergy is to make sure people around them know. "Students are also encouraged to make sure their friends are aware of the allergy so they can render assistance and if living in the dorms are encouraged to share the information with their RAs."