When you think of allergies, you might picture watery eyes, sneezing and runny noses. But unlike an allergy to spring flowers, a tree nut or peanut allergy can cause difficulty breathing, fainting and other very serious health problems.
A peanut allergy is the second most common food allergy, behind milk allergies, occurring in about 2% of children. Tree nut allergies occur in about 1% of kids.
“Allergies have a genetic association, but there isn’t a specific gene that points to allergens,” said Dr. Rajeev Kishore, director of Akron Children’s Center for Allergy and Immunology. “If a father has a nut allergy, it doesn’t necessarily mean his son will get it. You can’t predict it. All you can say is a child may have a higher risk for having a nut allergy.”
He further explains, if both parents have an allergy, there’s a 55% chance their child will have it, as well. If one parent has an allergy, there’s a 40% chance.
Symptoms of a tree nut or peanut allergy
A person with tree nut or peanut allergies could have a mild reaction — or it could be more severe. An allergic reaction usually happens right away, but some people can have another reaction a few hours after they eat a tree nut or peanut. A reaction may include bumpy rashes, or swelling around the mouth or face, vomiting, diarrhea, coughing and wheezing, or fainting.
In the most serious cases, a tree nut or peanut allergy can cause anaphylaxis, a sudden, life-threatening allergic reaction. A person’s blood pressure can drop, breathing tubes can narrow and the tongue can swell.
Diagnosing a tree nut or peanut allergy
If your doctor thinks your child might have a tree nut or peanut allergy, he will probably send him to see a doctor who specializes in allergies. The allergy specialist will ask him about past reactions and how long it takes between eating the tree nut or peanut and getting the symptoms, such as hives.
The allergist will most likely start with a skin test. This is a way of seeing how his body reacts to a very small amount of the nut that is giving him trouble. The allergist will use a liquid extract of the nut that seems to be causing symptoms. He also may use liquid extracts of other common allergy-causing foods or substances.
The doctor will make a little scratch on his skin (it will be a quick pinch, but there are no needles!). Different extracts will go on the different scratch spots, so the doctor can see how his skin reacts to each one. If he gets a reddish, itchy, raised spot, it shows that his is allergic to that food or substance.
If a child has a positive skin test, but hasn’t ingested peanuts or tree nuts, his doctor may conduct a food challenge in a controlled environment to fully determine if there’s an allergy.
“A diagnosis is made by 2 results,” said Dr. Kishore. “A positive skin test and symptoms after a child has ingested peanuts or tree nuts. A positive skin test alone doesn’t necessarily mean a child has an allergy. There’s only a 50-50 chance.”
Some doctors may also take a blood sample and send it to a lab. That’s where it will be mixed with some of the food or substance your child may be allergic to and checked for certain antibodies.
“We can look at blood levels for allergy antibodies to help us identify whether a food challenge is the best next step,” he said. “If antibodies are high, we may not conduct a food challenge due to the high risk of life-threatening symptoms.”
It’s important to remember that even though the doctor tests for food allergies by exposing patients to a very small amount of the food, you should not try this at home! The only place for an allergy test is at the doctor’s office, where they are specially trained and could give your child medicine right away if he had a reaction.
Treating a tree nut or peanut allergy
There is no special medicine for tree nut or peanut allergies and many people don’t outgrow them.
“There’s a 25-30% chance kids allergic to peanuts will outgrow it naturally. For tree nuts, there’s a 10-15% chance,” said Dr. Kishore. “But, if a child hasn’t outgrown the allergy by adolescence than it’s unlikely they’ll ever outgrow it.”
In the meantime, the best treatment is simply to avoid the nut. That means not eating that nut, and also means avoiding the nut when it’s mixed in foods.
Staying safe means reading labels and paying attention to what they say about how the food was produced. Some foods don’t contain nuts, but are made in factories that make other items that do contain nuts. The problem is the equipment can be used for both foods and leads to cross-contamination.
If your child has a serious tree nut or peanut allergy, you should create a plan for how to handle a reaction, just in case one occurs. That way your child’s teachers, the school nurse, his basketball coach, his friends — everyone will know what a serious reaction (anaphylaxis) looks like and how to respond. To immediately treat anaphylaxis, doctors recommend that kids with a tree nut or peanut allergy keep a shot of epinephrine with them.