Food allergies occur when your body reacts negatively to allergens (harmless food proteins) in certain foods. These reactions can range from mild to severe and can even become life threatening. Food allergies are most common in babies and children, with some children growing out of them as they get older. But, food allergies can occur at any age and follow a child throughout their entire life. Often they are more common in children with a family history of food allergies.
Common Allergies
Any food can cause an allergic reaction, but there are food groups that more commonly cause allergies such as:
- Cow’s milk/dairy products
- Eggs
- Peanuts
- Soy
- Wheat
- Nuts from trees such as walnuts, pistachios, pecans, and cashews
- Fish such as tuna, salmon, and cod
- Shellfish such as shrimp and lobster
- Sesame and it’s products
Peanuts, nuts, milk, and sesame are the most common causes of severe reactions, but allergies can also occur in other groups such as meats, fruits, vegetables, and grains! Allergies can be to a whole food group or to just one specific food. Your child may be allergic to many different beans like green beans or soybeans or just peanuts (which are actually a type of bean, not a nut!)
Symptoms
Each child’s food allergy symptoms may differ, and can develop after eating, inhaling, or coming in contact with their food allergen. Symptoms develop when the body’s immune system overreacts to certain foods and may include:
- Skin: hives, itching, rashes, swelling
- Breathing: sneezing, wheezing, throat swelling, coughing, nasal congestion, runny nose
- Gastrointestinal: nausea, vomiting, diarrhea, abdominal pain, cramps, trouble swallowing
- Circulation: pale skin, light-headedness, chest pain, feeling faint, confusion, loss of consciousness
In Babies
Food allergy symptoms may appear differently in infants including eye rubbing, repeatedly sticking their tongue out, excessive crying, back arching, and decreased muscle tone.
Treatment
Emergency
A severe allergic reaction, called anaphylaxis, is treated mainly with a medication called epinephrine. This medicine is available in an auto-injector pen and a nasal spray for emergency use during anaphylaxis. If your child has a food allergy, you should always have at least 2 doses of epinephrine readily available at all times- whether in an auto-injector or nasal spray form. Epinephrine is prescribed by your pediatrician or an allergist/immunologist. Talk to your child’s doctor about what to do if symptoms do not improve quickly after the first dose of epinephrine.
If your child experiences anaphylaxis, give them epinephrine immediately, then call 911 for further treatment and to be transferred to a hospital. Anaphylaxis is a very serious reaction and can become life threatening very quickly.
During a reaction, you may also use an oral antihistamine such as diphenhydramine (also known as Benadryl), but never in the place of epinephrine.
You may also want to get your child some form of medical identification jewelry such as a bracelet that lists their food allergy. This should be worn at all times to ensure that if your child is not with you, those around them will know to help them avoid their allergens and what to do if they begin having a reaction.
Prevention
The best and most obvious way to prevent an allergic reaction to food is to avoid the food and any foods that contain it or products of it. You can also use:
- a medication called omalizumab to stop an allergic reaction from becoming severe if your child is exposed to their allergen
- a treatment called oral immunotherapy to desensitize your child’s immune system to their allergen. This treatment introduces very small amounts of the food slowly, increasing the amount each time.
These treatments do not cure your child’s food allergy, and they will still need to avoid the food. But, it can help lessen the reaction over time and prevent a severe or life threatening reaction from occurring. These must be prescribed by an allergist or immunologist.
Early Introduction
Introducing your child to common allergens starting around 6 months of age can help lower the risk of developing an allergy to them. Delaying this introduction can actually raise their risk of developing an allergy. Offer common allergens like peanuts, eggs, dairy, and sesame in controlled amounts and watch closely for any type of reaction. If your child has a family history of eczema or allergies, check with your pediatrician before introducing these allergens.
Diagnosis
If your child has a reaction after eating, your pediatrician will try to determine which food caused the reaction, which may be difficult if your child was eating a meal with many ingredients. If your child has ongoing issues such as rashes or stomach pain, there may be more than one food in their diet that is causing the reactions. You may be referred to an allergist for allergy testing, which can determine which foods and other allergens your child is allergic to.
The doctor will asked questions about what foods were eaten, how long after eating did the symptoms start, how severe the symptoms were, how long the symptoms lasted, and what treatments you gave and how effective they were. They will also perform a physical exam. Using this history and physical exam, your doctor will determine if allergy testing is needed.
Allergy tests involve a skin prick or “scratch” test and/or blood test to help narrow down which allergens caused the reaction. Unfortunately, these tests are not always reliable and it is possible to get a false positive or false negative result.
Fast-Acting vs. Slow-Acting
The most common kind of food allergy is fast-acting allergies (IgE-Mediated), which occurs when your body makes a special protein antibody called immunoglobulin E (IgE) that reacts to certain foods. These reactions happen fast, within minutes or a few hours after eating the food.
There are also slow-acting allergies (non-IgE Mediated), which do not use the IgE protein and typically take longer to show signs- even days after eating the food. Examples include:
- Food protein-induced enterocolitis syndrome (FPIES)- mostly affecting babies and young children and mimicking stomach bug symptoms such as vomiting and dirrhea.
- Eosinophilic esophagitis (EoE)- symptoms in infants include feeding issues, poor weight gain, and vomiting. Older children may have trouble swallowing, heartburn, and food sticking in the esophogus.
Not an Allergy
Foods can cause other types of symptoms and illnesses that may be confused with allergies. These are not food allergies:
- Food poisoning- causes diarrhea and/or vomiting but is caused by bacteria in spoiled or undercooked foods
- Drug side effects- certain ingredients like caffeine can make your child shaky or restless
- Skin irritation- can be caused by acids in foods like orange juice or tomato products
- Diarrhea- can happen in small children from too much sugar, like in fruit juice
Intolerance/Sensitivity vs. Allergy
Not all food reactions are “allergies”, as they do not all involve the immune system. For example, lactose intolerance is when someone has trouble digesting milk sugar, causing stomach pain, gas, or diarrhea. People may also have reactions to chemicals, dyes, and preservatives in foods. These are typically sensitivities, not allergies, and they are much less common.
Outgrow
Thankfully, children often outgrow their childhood allergies with the majority of milk, egg, wheat, and soy allergies going away by age 5! Some allergies, though, stick around longer. Only 20-25% of children with peanut allergies and only 10% of kids with tree nut allergies outgrow them. Repeated testing throughout life can track your child’s allergies and see if they are going away as they age.
Living with an Allergy
Avoiding Foods
- Store-bought foods: read food labels carefully, as ingredients can change over time and foods that you never expect to have your child’s allergen in them, may indeed have it! Allergens may be hidden behind terms like “natural flavors” or “spices” which can include a variety of unlisted ingredients. Many food labels contain precautionary statements like “may contain…” to indicate which allergens are present in the food. You may even need to contact the manufacturer to get the exact ingredient list!
- Homemade foods: if you use the food your child is allergic to at home, be extra careful not to accidentally mix it into your child’s safe foods. Always use clean utensils, plates, pans, and serving trays to avoid cross-contamination. Also, store unsafe foods away from safe foods.
- Food at restaurants: Seemingly safe foods can be cross-contaminated or hidden in prepared foods and cause an allergic reaction. Plan restaurant outings carefully and be sure to communicate clearly with restaurant staff about your child’s allergy. Speak to someone who prepares the food and knows the ingredients well.
Anaphylaxis Action Plans
If your child will be away from you like at a family member or friend’s house, at school, daycare, or a camp, have a detailed written plan for caregivers. This plan should include how to avoid problem foods, how to recognize a reaction, how to treat a reaction, and where/how to get medical care. Check out “Create an Allergy and Anaphylaxis Emergency Plan” for more tips on creating one!