Food Allergies

Food Allergies

Food allergies are increasing in prevalence.  Children are more affected than adults.  Based on a self-reported questionnaire (which may overestimate true food allergy) as noted in the 2018 Food Allergy Practice Parameters it was noted 8% of children have food allergies.  The true prevalence is not clear based on methodology/population differences between different studies.  Furthermore, the types of adverse food allergy reactions can include food induced anaphylaxis, Eosinophilic Esophagitis, FPIES (Food Protein-Induced Enterocolitis Syndrome), oral allergy syndrome (aka pollen-food allergy syndrome), and in very young children/infants-atopic dermatitis exacerbations.

Common Food Allergies

• Peanuts are a common food allergen. Many public locations declare themselves “nut-free” to prevent the often-severe reactions associated with a peanut allergy.
• Milk is a fairly common food intolerance in children — 2% to 3% of those younger than age 3 are allergic to milk.  In the great majority of individuals’ milk allergy resolves, occasionally milk allergy will persist into adulthood.
• Eggs also are a common allergy in children, similar to milk most resolve in childhood.
• Tree nuts encompasses may different types, including, but not limited to pecan, almond, cashew, hazelnut, walnut, pistachio.  But coconut is not considered a tree nut and although some individuals can be also allergic to peanut, tree nuts do not cross react with peanut and many individuals who are allergic to tree nuts can tolerate eating peanut.
• Soy and soy products are a common food allergy in children, but many outgrow it.
• Sesame is now considered a major food allergen and must be listed when present in a food
• Wheat allergy also must be listed when present in a food product. Wheat allergy like milk, egg, and soy often resolves during childhood.
• Shellfish allergy which may occur in childhood is the food most commonly developing during adulthood.  Of note, shellfish allergy is due to allergy to a specific type of protein called tropomycin and is NOT due to iodine allergy and does NOT cross react with radiocontrast media.  Also shellfish does not cross react to finned fish.
• Fish allergy is one of the most common food allergies and does not cross react with shellfish.

Symptoms

Food allergy symptoms vary, depending on the person, the amount of the allergen consumed, and the level of the allergy. But typical symptoms of food allergies are often similar. They can appear as any or all of the reactions listed below:

• Itching of the mouth.
• Hives, skin rashes.
• Nasal congestion or runny nose.
• Wheezing.
• Upset stomach or severe nausea. Abdominal pain, cramping, vomiting.
• Confusion, dizziness.
• Anaphylaxis. This reaction is described below.
• Regarding eosinophilic esophagitis, results in an accumulation of eosinophils within the lining of the esophagus.  Therefore, this condition presents differently compared to other food allergic reactions.  This condition is addressed in more detail under the Eosinophilic Esophagitis (EoE) section.

Anaphylaxis

Anaphylaxis is less common than other allergic reactions, but this potentially fatal food allergy reaction can strike within minutes.

A secondary reaction, called a biphasic reaction, is a recurrence of anaphylaxis and in the majority of patients can occur between 4 and 24 hrs.

Anaphylaxis can be fatal. It requires emergency treatment.

Causes

Food allergies are caused by the body’s immune system interacting with certain foods. The immune system responds by attacking as if the food were a harmful substance trying to invade the body.  Depending on the type of reaction, different immune mechanisms may be involved, but in the case of immediate/anaphylactic episodes a part of the food protein binds an antibody called IgE which leads to massive release of allergic chemicals from mast cells and basophils.

Exposure types

• Inhalation. This occurs when someone breathes in airborne particles, such as in a bakery or kitchen where flour is used.
• Skin contact. This happens when foods or ingredients touch the skin, either directly or indirectly.
• Ingestion. The most common form of exposure happens when someone consumes a food or ingredient allergen.
• Less common exposures leading to allergic reaction may occur through touch (such as if a mother eating peanut butter then kisses her child on the cheek) or inhalation (This occurs when someone breathes in airborne particles, such as in a bakery or kitchen where flour is used.) usually leading to less severe reactions, such as a contact hive as it relates to the above example of a mother kissing her child.

Risk Factors

• Age. Infants and children have a higher risk of developing food allergies.
• Family history. A person is more likely to develop food allergies if there’s a family history of allergies, but having a family member is not an indication to test family members for food allergy unless the individual has a history consistent with food allergy.
• Gender. Women tend to have a higher prevalence of food allergies than men.
• Asthma. People with asthma are more likely to develop food allergies.
• Other allergies. People with other allergies are more likely to develop food allergies, and if you are allergic to one food you are more likely to develop an allergy to another type of food.
• Routine indiscriminant food allergy panels are NOT recommended and food allergy testing should be performed when there is a history consistent with a food allergy.

When to see a doctor

If you have a bad reaction to a specific food or ingredient, it’s a good idea to consult an allergy specialist. Tests can be done to determine the responsible allergens, and a treatment course can be created.

More severe reactions may require an urgent care or emergency room visit. Post-visit, seek the counsel of an allergist to analyze, treat, and manage food allergies.

Prevention and Treatment

• Epinephrine is the first-line emergency treatment for anaphylaxis. Those at risk often carry two epinephrine auto-injectors (ie, EpiPens/Auvi-Q) in case of a later, secondary reaction.
• Medical alert bracelets inform responders of a person’s potential allergic reactions. The information listed on the bracelet can speed proper treatment.
• Avoidance and education are key to effective allergy management. Read labels, avoid potential allergens, learn safe food preparation, and understand cross-contamination risks.
• Oral allergen immunotherapy gradually introduces allergens to a patient, in order to build their immunity. Specifically, people with peanut allergies may benefit from an FDA-approved treatment called Palforzia, which contains pharmaceutical grade peanut flour. It is administered in series of increasing doses to reduce peanut allergy sensitivity the patient and reduce adverse reactions to accidental exposures (this reduces the risk of accidental peanut exposure, but is not a cure).

Get Help with Your Food Allergy

The allergy and immunology specialists at Florida Medical Clinic provide a full scope of specialized care to patients with all types of allergies. For a consultation about food allergies, contact us today for an appointment.

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