MYTH My child has diarrhea every time he drinks cow’s milk. He must be allergic to it.
FACT The child may not necessarily be allergic to the milk. He may only be intolerant to it. Food allergy happens when the immune system overreacts to a harmless food protein and produces antibodies, usually immunoglobulin E (IgE) antibodies, to fight it. Upon repeated exposure to a small amount of the problem food, the IgE antibodies can trigger mild symptoms such as itching, hives, vomiting and diarrhoea. Or it can trigger a more serious reaction called anaphylaxis which constricts the airway, and causes blood pressure to drop or even death.
Food intolerance does not usually involve the immune system and is rarely life-threatening, although it can cause abdominal cramps, bloating and diarrhoea. Diarrhoea may happen after drinking milk because of lactose intolerance or trouble digesting the milk sugar lactose.
MYTH Frying destroys the allergen in food and makes it safe to eat.
FACT The food proteins in allergenic foods such as eggs, milk, peanuts, tree nuts and shellfish do not break down easily when exposed to heat or to the acid in our stomachs. But these proteins can undergo molecular changes which make them less allergenic. For instance, boiling peanuts tend to make them less allergenic compared to roasting them.
MYTH A mixed dish, for example, a salad with peanuts, is safe to eat after the allergen, the peanut, has been removed.
FACT Traces of the peanut would still be left in the salad which could cause a reaction. In people who are highly allergic, that is, who have very high levels of IgE antibodies, all it takes is a trace amount of the substance, which could be invisible to the eye, to trigger a severe allergic reaction.
MYTH If I am allergic to peanuts, I should not take soya beans and green beans too, as they are all from the bean or legume family.
FACT People with a peanut allergy can tolerate other beans 95 per cent of the time. However, three out of every 10 people with peanut allergy are also allergic to tree nuts, such as almonds, walnuts and cashews, and are advised to avoid them.
MYTH Food allergy is for life.
FACT Most children outgrow their food allergies by the age of 10, with the exception of those who are allergic to peanuts, tree nuts and shellfish. Only two out of every 10 children will outgrow these allergies.
MYTH A child with egg allergy cannot be vaccinated.
FACT The measles, mumps and rubella vaccine, which has minute amounts of egg protein, can be given safely to a child with egg allergy. But if he has had a severe reaction to eggs, he should avoid the flu vaccine, which is made using a higher amount of egg protein.
MYTH Eczema is caused by food allergy.
FACT Most cases of eczema are not caused by food allergy. However, food allergies may trigger or cause persistent eczema in infants and children. Food allergies are seldom associated with adult eczema.
Source: Dr Liew Woei Kang, a visiting consultant paediatric allergist and immunologist at Mount Elizabeth Hospital