Understanding food allergy is crucial for your and your child’s safety

Understanding food allergy is crucial for your and your child’s safety

Food allergy is an adverse immune response to specific food proteins, resulting in chronic inflammation of the gastrointestinal tract lining. Only a small number of patients are allergic to carbohydrates and fats. Food allergy can occur in children and adults, often accompanied by other allergies, especially severe atopic dermatitis in children.

Dr. David J. Hill, an Australian allergist, reported that global surveys of food allergy prevalence found rates of 5-7% in toddlers and 2-3% in adults. Food allergies vary by country, reflecting dietary differences. In Asia, Malaysia, Japan, Thailand, and South Korea, the most common food allergies are to seafood, soba noodles, and wheat flour spaghetti. In Europe, the US, and Australia, legume and tree nut allergies are also common. Food allergies in children are similar, with cow's milk and egg allergies being the most common.

Food allergy in Thailand

Food allergies are common in Thailand, affecting 5% of the population, especially children. Dr. Oraphan Poachanukoon, an allergist at Thammasat University Hospital, reports that over 50% of patients admitted with anaphylaxis are allergic to cow's milk, eggs, or seafood. These foods are the major causes of anaphylaxis in Thailand, with drug and insect sting allergies less common. Dr. Poachanukoon emphasizes that food allergies are a significant issue that requires more attention, especially regarding proper treatment.

Food allergy symptoms

Food allergies can cause a range of symptoms, including:

• Skin: Hives, atopic dermatitis, or allergic contact dermatitis, accompanied by swollen lips and eyelids.
• Gastrointestinal: Episodic abdominal pain, nausea, diarrhea, or blood in the stool.
• Respiratory: Dyspnea, excessive phlegm, or runny nose. In severe cases, dizziness, fainting, syncope, or death due to respiratory failure or cardiovascular collapse may occur.

Allergy-causing foods

The most common food allergens causing allergies in children are cow's milk, soy milk, eggs, and wheat. In adolescents and adults, seafood is the most common allergen.
Exposure to food allergens may occur through the following routes:

• Ingestion: Eating food that they are allergic to without knowing it.
• Cross-contamination: Touching or kissing someone who has eaten allergenic food or sharing utensils during preparation or eating.
• Adding condiments that contain allergenic ingredients
• Inhalation: For example, people with wheat allergy may experience baker's asthma or coughing if they inhale wheat flour.

Why people are allergic to food?

The exact cause of food allergies is unknown, but they are thought to result from a combination of genetic, environmental, and nutritional factors. One hypothesis is that food allergies are more common in young children because their gastrointestinal systems are still developing. Additionally, infants who are not breastfed may be at increased risk.

Precautions for patients with food allergies

In addition to the avoidance of the most common food allergens in the age group mentioned above, other precautions for patients with food allergies include knowing:

• Immediate reactions: These reactions occur within 2 hours of eating the allergen and can be severe. The next time the patient eats the allergen, the reaction may be sooner and more severe.
• Delayed reactions: These reactions occur 2 hours or more after eating the allergen and can be difficult to diagnose. A skin patch test or oral food challenge test may be necessary to confirm the diagnosis.
• Amount: Even a tiny amount of an allergen can cause anaphylaxis in some patients.
• Parts of the food: Any part of an allergenic food can cause a reaction, even if it has been cooked, e.g., shrimp fat.
• Cooking methods: Cooking may reduce the allergenicity of some foods. For example, children with cow’s milk or egg allergy can consume cooked cow’s milk or egg without allergic reactions.

Diagnostic tests for food allergy

Medical methods to confirm food allergy allergens include:

1. Skin prick test: This test is suitable for patients with immediate allergic reactions and takes about 60 minutes. Patients should stop taking antihistamine medications at least 1 week before the test.
2. Skin patch test: This test is suitable for patients with delayed allergic reactions and takes at least 48 hours to complete. Patients should avoid touching the test area on their skin before reading the results. Like the skin prick test, patients must stop taking antihistamine medications at least 1 week before the test.
3. Oral food challenge test: This test is a highly accurate way to confirm the diagnosis of food allergy but should be performed under the medical supervision of a specialist with rescue medications and resuscitation equipment ready to use in case of anaphylaxis.

Most doctors can diagnose food allergies based on a patient's medical history, physical examination, and skin prick test results.

Treatment for food allergy

• Avoidance: The best way to treat food allergy is to avoid eating the allergen and any foods that contain it.
• Cow's milk allergy: Some children with cow's milk allergies outgrow their allergy over time, after avoiding cow's milk and products containing milk for 1 year.
• Seafood allergy: Seafood allergy is typically a lifelong condition with no cure.

Treatment for severe food allergy (anaphylaxis)

Patients with severe food allergies should inject epinephrine (adrenaline) into their muscles immediately after an allergic reaction. The injection can be done by themselves or their caretakers before reaching a hospital. Epinephrine is a life-saving medication that helps to reverse the symptoms of anaphylaxis.

Epinephrine auto-injectors (such as EpiPen) are the preferred method of epinephrine administration for patients with severe food allergies. However, these devices are expensive. As a result, some doctors may prescribe epinephrine-prefilled syringes for patients who cannot afford EpiPens.

Epinephrine prefilled syringes have some limitations. They must be kept refrigerated at the right temperature and in a box that prevents light exposure. They are also only stable for a short time, typically 2 months. Patients must replace their prefilled syringes every 2 months or immediately after they become discolored or contain precipitates.

How to self-administer intramuscular adrenaline

1. Locate the injection site.
   The preferred injection site is the outer mid-thigh. It is convenient because it has large muscles with a good blood supply, allowing adrenaline to be absorbed quickly and avoiding damaging the femoral artery and nerve. You do not need to clean the injection site before administering adrenaline, which can be injected through clothing.
2. Inject the epinephrine.
   If you are using an epinephrine prefilled syringe, hold the syringe perpendicular to the skin and insert the needle as deep as it will go. Most needles for this type of administration are 0.5-1.0 inches long, and you should administer the medication in the quantity the doctor prepared in the syringe.
3. Seek medical attention.
   After injecting epinephrine, seek medical attention immediately for further treatment and monitoring for at least 24 hours. Some people may have recurrent allergic reactions even if they are not re-exposed to the allergen.

Medical alert accessories for food allergens

Medical alert accessories can help to ensure that people with food allergies receive prompt and appropriate medical treatment in the event of an allergic reaction. Some usual medical accessories alerting for food allergies include t-shirts, bracelets, necklaces, wristbands, and anklets, typically engraved with a person's name, medical condition, and any food allergies.

Self-testing for food allergies

Eating food you suspect you may be allergic to at home is risky and could be life-threatening. If you are concerned about a food allergy, consult a doctor for allergy testing in a hospital setting.

Preventive measures for children at risk of food allergies

1. Breastfeed exclusively for the first 4-6 months.
2. Introduce complementary foods one type at a time after 4-6 months. First, start with hypoallergenic foods, such as egg yolks, pork, and poultry. Add a new food type every week if there is no allergic reaction. There is no need to avoid common allergenic foods unless the child has a biological parent or sibling with a peanut allergy, in which case, perform a peanut allergy assessment before the child starts eating peanuts.
3. Mothers do not need to avoid any foods during pregnancy or breastfeeding unless they or the baby has a history of allergic reactions to certain types of foods.
4. Mothers should not consume too much cow's milk during pregnancy or breastfeeding (not more than 1 and 2 glasses a day, respectively, in the second and third trimester). If the mother cannot breastfeed, she should use formula milk suitable for cow's milk allergy.
5. Children at risk of food allergies should start eating seafood after their first birthdays.

These recommendations are based on the latest research on food allergy prevention. However, it is important to consult your doctor about what is best for your child's needs.