Food allergy occurs, when the body immune system sees certain foods as harmful, thereby causing an unpleasant reaction. Food allergies can cause serious and deadly reactions in kids, if not properly handled. Dr. Oluwafunmilayo Funke Adeniyi, a paediatrician in the Department of Paediatrics, Lagos University Teaching Hospital (LUTH) discussed food allergies in children, what triggers it and how to reduce the risk of kids developing it. GERALDINE AKUTU reports.
What is food allergy?
Food allergy is a clinical condition, where the body makes antibodies (Immunoglobulin E (IgE)) to a specific food. The job of the body’s immune system is to identify and destroy germs, such as bacteria or viruses that make you sick. A food allergy results, when the immune system mistakenly targets a harmless food protein – an allergen – as a threat and attacks it. Initial exposure to the food may not produce severe reaction, but the child may become sensitised and when the food is next eaten (or sometimes just comes in contact with the skin), it triggers an immune system response, which results in the release of histamine and other substances in the body. These cause various symptoms, depending on where in the body they are released.
Signs and Food allergy
The following are the signs and symptoms of food allergy regardless of the allergen:
Skin system: swelling, itching, warmth, redness and rashes, Respiratory system (breathing): coughing, wheezing, shortness of breath, chest pain/tightness, throat tightness, hoarse voice, nasal congestion or hay fever-like symptoms (runny itchy nose, watery eyes and sneezing), difficulty in swallowing.
Gastrointestinal system (stomach): nausea, pain/cramps, vomiting, diarrhoea and some children may actually pass blood in the stools.
Cardiovascular system (heart): pale/blue colour, weak pulse, passing out, dizzy/lightheaded, and shock. Others: older children may describe anxiety, feeling of “impending doom”, headache, and metallic taste. The most dangerous symptoms of an allergic reaction, which is usually referred to as anaphylaxis are:
• Difficulty with breathing caused by swelling of the airways, including a severe asthma attack for people, who have asthma.
• Drop in blood pressure, causing dizziness, light-headedness, feeling faint or weak, or passing out. Both can lead to death, if untreated.
Having said this, it is important to note the symptoms of ‘classic’ allergy, which are rashes, wheezing, itching, severe gut symptoms and very rarely, sudden collapse i.e. anaphylaxis.
How long does it take to have allergy in children?
An allergic reaction usually happens within minutes after exposure to an allergen, but sometimes it can take place several hours after exposure to the allergen. In children with the immune mediated or IgE mediated food, allergy symptoms occur within minutes up to two hours after ingestion of the food. These symptoms usually recur on exposure to the food on every occasion and may be mild or severe, associated with anaphylaxis. The symptoms of ‘classic’ allergy, as such, are rashes, wheezing, itching, severe gut symptoms or (very rarely) sudden collapse.
What are the most common food allergies in children?
Allergy can occur to a single food or to many foods. Allergy to many foods is a more severe form of allergy, and is referred to as multiple food allergies.
The common allergenic foods i.e. food that induce allergies, include cow’s milk, dairy products, egg, seafood (fish and shrimps), wheat, soy and peanuts. The commonest food allergy in children is cow’s milk.
Is there a cure for food allergy?
There is no direct cure for food allergy. The condition is best managed with elimination diet i.e. avoidance or exclusion of the offending food from the diet and subsequent substitution. For example, in a child with cow’s milk protein allergy, the milk should be removed from the child’s diet and a substitute in the form of soya milk, or hydrolysed formula (i.e. milk that the protein has been broken down to peptides) or amino acid formula, which can readily be digested and does not cause reactions in the child.
When the child is up to six months and weaning is commenced, solids should be introduced gradually and one food at a time. This should be from the least allergenic foods, i.e. cereals, then vegetables and fruits, then chicken, eggs, fish and lastly nuts.
How can parents handle their children’s food allergies?
If a severe allergy has been identified in a child, it is important the parents ensure that the child avoid even the tiniest amounts of the trigger food. Very occasionally, reactions can occur, even when the child has had skin contact with the offending food. A fish-allergic person may react by being in a kitchen, where fish is being cooked. The parents should do gradual introduction of the allergenic foods in infancy, as described earlier.
Children, parents and caregivers should be educated on common ingredients, reading food labels and how to safely avoid allergens. Children and parents should also be aware of appropriate, safe, cost-effective, freely available and nutritionally adequate substitutes for the avoided foods.
As well as avoiding the offending food, the allergic child should be provided with appropriate emergency treatment, should accidental exposure occur. Depending on the severity of the reaction, this may be adrenaline to be given by injection, antihistamines, steroids, or all of these. The exact details of such treatment will need to be decided by the doctor in charge of the child. The parents should ensure that an allergy specialist or dietician, who is experienced in food allergies and paediatric gastroenterologist, sees the child regularly.
Children affected by severe food allergy can still participate in all normal activities, school, work or leisure, but the parents should give appropriate support and understanding.
Can a child outgrow food allergies?
Usually, children who have cow’s milk allergy become tolerant of cow’s milk, as they grow older and outgrow their allergy by the age of two to three years. Children are usually re-evaluated at regular intervals to see if they have developed tolerance. Generally, younger children with milk, soya and egg allergy are reviewed every six to 12 months and older children every one to two years. Tree nut, fish and shellfish allergy may be life long, but re-evaluation should be performed every two to four years to determine whether re-challenges are appropriate or exclusion needs to be continued.