By Dr Dave Ong
Common childhood atopic/allergy-related conditions include:
Asthma, atopic eczema and allergic rhinitis/rhino-conjunctivitis have all been covered in previous articles under Parenting Tips and Health Topics A-Z. This article will focus on the diagnosis and management of food allergies, as well as the prevention of common childhood allergies.
A food allergy is an immune system-driven adverse reaction to certain foods. This means that the body’s immune system, which usually fights infection, produces substances that cause the body to react badly to that food. It is estimated that not more than 5% of children younger than 12 years old have food allergies and the prevalence declines with age to about 1% in adults. Children usually outgrow some food allergies such as milk and eggs, while other allergies such as seafood or nut allergies are more likely to remain.
The cause of food allergy is unknown. Children with a strong family history of food allergies are at higher risk of developing the same condition, suggesting that genes may contribute to developing food allergy. However, the exact genes that are responsible are unknown. Environmental factors are also thought to play a part. Studies have shown that delayed introduction of foods into the baby’s diet tend to increase the risk of developing food allergy. It is unclear how much this may hold true in an Asian population. This also means that the introduction of solid foods should not be delayed beyond 4 to 6 months of age, including so-called “allergenic” foods like egg and peanut.
If your child has food allergies, he or she may experience the following symptoms very quickly after consuming the food allergen:
The reaction tends to happen within 30 minutes after eating the offending food and can last up to 24 hours.
Skin prick tests and blood tests can be done to help diagnose a food allergy. They are also used over time to track the likelihood of the child outgrowing that particular allergy.
The standard advice is to avoid the food allergen. Immunotherapy, which reduces the risk of allergic reactions and improves quality of life, is available for certain food allergies such as peanut, cashew, pistachio, egg, milk and wheat. The child should preferably be 5 years old and above although exceptions do exist. This can only be done by a paediatrician sub-specialising in allergy, with the appropriate facilities in place.
If a reaction is clearly linked to the exposure to particular foods, you should consult your child’s paediatrician. In the meantime, your child should avoid the suspected food. Even small amounts of it may cause a similar reaction.
It is good to keep a food diary if you are unsure whether the food causes your child’s condition to worsen. It may help to indicate a hidden ingredient in the food that is causing the reaction. Bring the food diary with you when you consult your child’s paediatrician.
Do not make the mistake of labelling your child with multiple food allergies without good evidence. Your child is growing and needs a variety of food to ensure adequate nutrition. Do consult your child’s paediatrician for proper diagnosis.
Any baby can develop an allergy. It has long been known that allergies tend to run in families. If one or both parents or other siblings have an allergic disease, an infant is more likely to develop an allergic condition, such as food allergy or atopic dermatitis (eczema). Your feeding choices can also make a difference in your baby’s likelihood of developing allergies, and your child’s nutrition can play a critical role in prevention.
Note: The following recommendations for your baby’s nutrition and prevention of allergies are not intended for infants who have already developed an allergic condition.
In the past it was suggested that avoiding certain foods during pregnancy or breastfeeding could reduce your infant’s chance of developing allergies. More recent information indicates there is no significant allergy prevention benefit to your baby if you avoid highly allergenic foods during this time. Foods considered highly allergenic include cow’s milk protein, soy, eggs, wheat, peanuts, tree nuts, fish and shellfish. Avoiding nutritious, highly allergenic foods such as milk and eggs is not recommended during pregnancy. Avoiding highly allergenic foods when breastfeeding is also not recommended. A healthy balanced diet which isrich in fibre, vegetables and fruit is recommended, because it provides many health benefits to the mother and infant during pregnancy and breastfeeding.
Up to 3 servings of oily fish per week may be beneficial, as there is some evidence that omega-3 fatty acids (found in oily fish) during pregnancy and breastfeeding may help prevent eczema in early life.
Whilst there is moderate evidence that probiotics during pregnancy and breastfeeding may help prevent eczema in early life, recommendations about probiotic supplements cannot currently be made because the optimal species and dose of probiotics that might have an effect is unclear. More research is required in this area before clear and specific recommendations can be made.
Note: This recommendation does not apply if you or your infant has developed a food allergy. Although not recommended, if you choose to avoid foods during pregnancy or lactation, dietary counseling with a nutritionist is recommended.
Breastfeeding is the best way to feed your infant, and there is no benefit of formula over breast-feeding to prevent allergic disease. If breastfeeding is not possible, a standard cow’s milk based formula can be given. There is no evidence that soy or goat’s milk formula reduce the risk of allergic disease when used in preference to standard cow’s milk based formula. Based on recently published systemic reviews of research studies, there is no consistent convincing evidence to support a protective role for partially hydrolysed formulas (usually labelled ‘HA’ or Hypoallergenic) or extensively hydrolysed formulas for the prevention of eczema, food allergy, asthma or allergic rhinitis in infants or children.
Breastfeeding is the ideal way to nourish your infant. Breast milk is least likely to trigger an allergic reaction, is easy to digest and strengthens an infant’s immune system. Exclusive breastfeeding is recommended for at least 4 months and up to 6 months of age because it may reduce the incidence of atopic dermatitis, early onset of wheezing, and the incidence of cow’s milk protein allergy.
Experts recommend exclusive breastfeeding until 4 to 6 months of age. The introduction of solid foods for your baby depends on their developmental readiness.
Your baby may be ready for solid foods when he or she:
Timing of certain foods should also be considered when introducing solid foods to your baby. Try introducing these single ingredient infant foods to your baby one at a time, every 3 to 5 days:
This slow process can give you the chance to identify and eliminate any food that may cause an allergic reaction. You do not need to avoid acidic foods for your baby (e.g. berries, tomatoes, citrus fruits and vegetables) that may cause a rash around the mouth. This is due to irritation from the acid in the food, not from an allergic reaction to the food.
Learn more on Weaning Your Baby onto Solids.
Highly allergenic foods can be introduced to your baby between 4 and 6 months of age, just as you would introduce any other solid foods. Highly allergenic foods that you can feed your baby include:
You may want to be cautious when introducing your baby to highly allergenic solid foods. One safe way to do this is to introduce the first tastes at home rather than at day care or a restaurant. You should introduce highly allergenic foods to your baby after other solid foods have been fed and tolerated, and with the first taste being at home. If no reaction occurs, then you can gradually increase the amount at a rate of one new food every 3 to 5 days.
You should to talk to your baby’s paediatrician before introducing a highly allergenic food for the following situations:
Some infants will develop food allergies regardless. Thus if there is any allergic reaction to any food, that food should be stopped and you should seek advice from your child’s paediatrician. Your child’s paediatrician may refer him/her a paediatric allergist/immunologist for further evaluation, depending on the clinical situation.
While the cause of food allergies are unknown, it has been suggested that family history and the environment contribute to a child developing food allergies.
After consuming the food allergen, children with food allergies may wheeze, experience shortness of breath, hives, swelling of the mouth area, vomiting or other symptoms.
Food allergies can be diagnosed through skin prick tests and blood tests, which can be done by a paediatrician sub-specialising in allergies.
Avoid suspected food allergens and help your child keep a food diary to track your observations. If you are unsure, consult your child’s doctor for a diagnosis.
Exclusive breastfeeding for babies up to 6 months of age strengthens the immune system and may reduce incidence of eczema, wheezing and cow’s milk protein allergy.
When introducing solids foods which are highly allergenic to your baby, first try this at home and gradually increase this at 1 new food every 3 to 5 days.
Want to find out more? You may be interested in these articles:
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