Food allergy

Last updated on: 20 April 2020 | Released on: 21 April 2017

Q1
What should I do if I suspect a food allergy? What kind of medical care should I seek?
A1
If you suspect a food allergy symptom in you or your child, you should first go to your neighborhood primary care doctor (family doctor).
Your primary care doctor will explain the symptoms and, if necessary, refer you to another medical care facility. You should consult with your doctor in detail regarding your diagnosis and treatment program (such as whether you or your child should be seen by a specialist, undergo testing, or receive specific therapies).
In order to receive the most appropriate treatment for your or your child’s symptoms, it is important to have ready the information your doctor will need from you. These will include the course of symptoms (how much of what was eaten, and what kinds of symptoms appeared how long after eating), as well as a list of questions and concerns you may have. Make sure you give your doctor an accurate account of the main points.
  • You can search for whether allergy specialists certified by the Japanese Society of Allergology are in your neighborhood.
Link
Information on medical care facilities
Q2
What is the “Allergic March”?
A2
Also called “Atopic March,” the term “Allergic March” refers to the tendency for patients with atopic factors to experience different allergic symptoms or disorders during their growth and development, either in a continuous or intermittent series or as an accumulation. These typically start with food allergies or atopic dermatitis during infancy, followed by asthma and allergic rhinitis in early childhood and later on in life.
The term also refers to the tendency for allergen sensitivity to change with a patient’s age, from food allergens to inhaled allergens (house mites, pet dander, pollen, etc.).
(Excerpted with partial modifications from Environmental Restoration and Conservation Agency’s “User-friendly Guide to Food Allergy Measures for Asthma Prevention (Japanese)”)
Q3
Is there a link between food allergies and atopic dermatitis?
A3
In “infant atopic dermatitis with food allergy involvement,” atopic dermatitis in infancy may be exacerbated by certain foods. Not all infant atopic dermatitis is associated with food; an estimated 50% to 70% are. Therefore, while people tend to assume that eczema and atopic dermatitis in infants are caused by food allergies, this is not necessarily the case. It is important not to jump to the conclusion that food is responsible, but to first practice appropriate skincare and topical treatment with ointments to alleviate skin symptoms. If symptoms do not subside with such care, then food allergies may be suspected and tests carried out.
Q4
What is the difference between immediate-type food allergies in children and in adults?
A4
In many pediatric cases, the allergens are chicken eggs, cow milk, and wheat flour. Many children outgrow these allergies (50% by age 3 and about 80% to 90% by age 6). Allergies which manifest during and after school age tend to be shellfish, wheat flour, fruit, fish, buckwheat, and peanuts. These allergies tend to be more difficult to outgrow and may require elimination over the long term, sometimes for life.
Q5
How frequently should a person with food allergies be tested?
A5
Chicken eggs, cow milk products, wheat flour, and soy, which are frequently the culprits in infant food allergies, can usually be eaten by 50% of patients by age 3 and about 80% to 90% of patients by age 6. It is therefore advisable to review the child’s elimination diet periodically and aim to terminate the elimination as early as possible. If the food allergy is of a type which is frequently outgrown, the child should have a diagnostic review about twice a year and, depending on test results, oral food challenges considered.
Q6
An allergy antibody test (allergen-specific IgE*) showed a positive response to multiple foods. Should all of these foods be eliminated from the diet?
A6
A positive IgE test does not necessarily mean the child will develop an allergic reaction to that food, and just because a food tested positive does not automatically mean it needs to be avoided. You should have a detailed consultation with your doctor about which foods to eliminate.
* Allergen-specific IgE test: A test which measures blood levels of IgE antibodies to different antigens (foods which cause allergies).
Q7
If a patient is allergic to chicken eggs and cow milk, should chicken meat and beef also be eliminated from the diet?
A7
Chicken meat and fish eggs do not cause chicken egg allergies and generally do not need to be avoided. Similarly, beef does not cause cow milk allergy and therefore usually does not need to be avoided. You should follow your doctor’s instructions and keep elimination to a minimum, and only to those foods which cause a reaction when eaten.
Q8
Sometimes, the product label of a processed or packaged food may indicate that it was “processed on the same manufacturing line as the ingredient X (e.g. shrimp).” Should someone who is allergic to the ingredient X avoid food items bearing such information on the label?
A8
Processed food manufacturers which handle food allergens in their facility are permitted to carry such cautionary statements outside the ingredients panel of a given product, even if the allergens are not used as ingredients of that product. This is to warn consumers about the risk of cross-contamination by tiny amounts of the allergen which may make their way into the food. Generally, such processed foods do not need to be eliminated since the allergen is not contained in those foods; however, check with your doctor.
Q9
If a person is allergic to cow milk, should he/she avoid anything with “lacto-” or “milk” in it, such as lactose?
A9
Cow milk must be indicated on the label as an allergen. However, just because something says “lacto-” or “milk” does not necessarily mean it should be avoided. To guard against the risk of accidental ingestion while widening patients’ choice of foods, it is important to use the allergen statement on the label to distinguish between foods which can and cannot be eaten.
  • Processed foods such as whole milk powder, nonfat dry milk, condensed milk, fermented milk drinks (sometimes called “probiotics”), and yogurt contain cow milk and must be avoided by patients with cow milk allergy.
  • While lactose contains trace amounts of cow milk protein from which it is made, it usually does not cause allergic symptoms unless ingested in large quantities. Consult with your doctor about the advisability of consuming products containing lactose.
  • Emulsifiers, Lactobacillus, calcium lactate, sodium lactate, and cacao butter are sometimes mistakenly considered to be milk-related products, but they are not. They have nothing to do with cow milk.
Q10
Do allergens change with cooking or fermentation?
A10
Different foods respond differently to cooking or fermentation. Chicken eggs are less allergic when cooked. This is why, even when a patient overcomes an allergy to cooked eggs, he/she still needs to be careful about eating raw, soft-boiled, or poached eggs. Milk and milk products do not become less allergenic with heating or fermentation. It is important to learn the characteristics of each food, follow your doctor’s instructions, and keep elimination to a minimum; only those foods which cause symptoms when eaten should be eliminated.
Q11
How should a patient on an elimination diet (cow milk and eggs) receive adequate nutrition?
A11
Substitutes for the eliminated foods should be used to ensure a balanced diet.

Substitutes for chicken eggs
Chicken eggs are a rich source of protein. It is essential to ensure adequate protein intake. Fish, shellfish, meat, soy products, cow milk, and milk products are good substitutes.

Substitutes for cow milk
Cow milk is a rich source of protein and calcium. Protein can be obtained by eating plenty of fish and shellfish, meat, soy products, and eggs. Calcium can be replenished with hypoallergenic powdered milk, soy milk, tofu, small fish eaten whole with bones, and seaweed.
Q12
Can a patient with a wheat allergy drink barley tea?
A12
Barley tea is made by steeping or boiling roasted barley kernels in hot water, and is not directly associated with wheat. However, some patients with wheat allergy may be instructed to eliminate all wheat variety foods including barley, in which case barley tea may also need to be eliminated.
Q13
My child has food allergies. How should I prepare for natural disasters?
A13
First of all, it is important to be as prepared as possible on an individual level.
  • Situations which may arise during a disaster include: (1) A lack of hypoallergenic foods; (2) Accidental ingestion of allergens at soup kitchens; (3) Delayed response in the event of anaphylactic shock; and (4) A lack of understanding and/or support from others regarding food allergies.
  • The following are some items which should always be in your disaster preparedness kit: (1) Emergency medication in case of accidental ingestion; (2) Foods which the patient is eating safely on a daily basis and which can be stored for at least several days (hypoallergenic alpha rice, hypoallergenic retort-pouch curry, hypoallergenic infant formula, etc.); (3) Maps and contact numbers of places where hypoallergenic foods are stored; (4) Food allergy alert card or other item with a clearly written list of eliminated foods.
  • For individual patients, it is essential to receive an accurate diagnosis of food allergies and have a clear understanding of which foods truly need to be eliminated. When a person is avoiding foods “just in case,” their sense of anxiety, as well as inconvenience, are amplified during times of disaster. It is also important to know whether a food must be eliminated completely, even down to trace amounts, or whether it can be eaten in certain amounts, and in the case of the latter, to make a point of eating it in manageable quantities on an everyday basis.
  • Have a week’s (at least 3 days’) worth of emergency foods in stock at all times, and replace them as they near their expiration date. Foods which the patient is eating safely on a daily basis and which can be stored for at least several days, hypoallergenic infant formula, hypoallergenic alpha rice (free of specified allergenic ingredients) which can be eaten without cooking, furikake seasoning, and hypoallergenic retort-pouch curry are some items which should be kept on hand on an ongoing basis and eaten periodically so that they feel familiar.
  • Have several doses of emergency medication on hand in case of accidental ingestion.
  • Allergy alert cards which carry food allergy information and a list of emergency contact numbers can be useful.

(Excerpted with partial modifications from Environmental Restoration and Conservation Agency’s “2014 User-friendly Guide to Food Allergy Measures for Asthma Prevention (Japanese)”)

Q14
If a breastfeeding baby has food allergies, should the mother also eliminate the foods from her own diet? What is the relationship between breastmilk and allergies?
A14
Generally speaking, there is no need to stop breastfeeding a child with food allergies. It is also generally unadvisable for breastfeeding mothers to eliminate certain foods from her diet in an attempt to prevent allergic symptoms from manifesting in her child.
Q15
If my child has an allergy and is going to attend nursery school, is there anything that I should ask the nursery school to do? And what kind of things should I pay attention to?
A15
Firstly, it is important to find out what kind of action the nursery school will take when it comes to food allergies.
  • In order to request the nursery school to deal with the situation, get your family doctor to fill out a Life Guidance and Management Form (seikatsu kanri shidō-hyō in Japanese) and present it to the nursery school. Then guardians and the nursery school should create and share a specific individual plan to deal with the allergy.
  • Complete elimination of the food that causes the allergic reaction from meals at nursery school is recommended by the Ministry of Health, Labour and Welfare. This is because incremental elimination as is employed in households, such as only allowing the food in question to be eaten in small amounts or if heated up, makes it easier for an accident to occur. Please understand that the approach of complete elimination is based on ultimate prioritization of safety for children at nursery school.
  • In order to ensure that children can enjoy a safe everyday life at nursery school, it is important to ensure sufficient collaboration between nursery school staff, family doctors (or the school doctor in some cases), and guardians. Make sure everyone knows who to contact in the event of an emergency.
  • In some cases, children with severe allergies need to be dealt with on a highly prioritized basis , so be sure to provide a detailed explanation of your child’s situation and ensure the nursery school understands it. You should also thoroughly check the nursery school’s handling of allergies, and periodically discuss it with the school.
  • It is said that around half of all children are able to eat foods that have the potential to cause allergic reactions at the age of around three, and 80 to 90% of children are able to do so at the age of six. In order to reduce the burden at home and to reduce concerns at mealtimes at nursery school, please regularly review whether or not a certain food still needs to be excluded from meals. If you decide that it is OK for your child to eat the food in question, have them eat it a few times first to check that there are no problems, and then please provide written notification that this food no longer needs to be excluded at nursery school.
Q16
If I restrict my diet during pregnancy, is it possible to prevent my child from getting food allergies?
A16
Currently, there is no scientific evidence indicating that the occurrence of allergies can be prevented in children by mothers removing certain foods from their diet during pregnancy. As such, avoiding certain foods to prevent the occurrence of allergies is not normally recommended to pregnant mothers.
Q17
What approach should I take towards immunizations for children with an allergy?
A17
Normally, just because someone is told they have asthma, atopic dermatitis, allergic rhinitis, hives, atopic diathesis, or other such problems it doesn’t make them unsuitable for immunization. Consult your family doctor, and have your child immunized at the appropriate age when they are in good physical condition.
  • The things that have been reported to be related to allergies in immunizations include vaccine stabilizers, preservatives, antimicrobial agents, chicken egg components used in culture media, and the vaccine fungus component itself. Recently, gelatin has started to be used in yellow fever vaccine (an optional immunization), but the amount contained is minute. The rate of occurrence of allergic reactions to preservatives and antimicrobial is extremely low, and normally it is not a cause for concern.
  • While the amount of chicken egg content in influenza vaccines differs somewhat depending on the manufacturer, it is a minute amount and as such is not enough to trigger an immediate allergic reaction. As such, even though a person may have an allergy to chicken eggs, they are normally able to receive influenza vaccines. If you have a strong allergy to egg white or guardians have serious concerns, have a thorough consultation with your family doctor or a doctor responsible for vaccinations.
Q18
I have a child who is about to start eating solids, but the older sibling has a food allergy. In order to prevent something similar, should I take actions such as delaying the younger sibling’s transition to solids or eliminating foods from the diet?
A18
Regarding the timing and dietary content of transitioning to solids, stick with the standard timing and content at first. There is normally no need to preemptively remove something from your child’s diet. Conversely, some of the latest research suggests that it may be better to have your child eat foods that can cause allergies earlier in order to prevent allergies from occurring. If there is a history of severe allergies in your family or you have other such concerns, it is recommended that you consult a doctor.