Food Allergy In Children

Many people suspect that their child may be allergic to certain foods.

In families where there is a history of asthma, hayfever or eczema, there is a greater possibility of having a food allergic or intolerant child. In food allergy there is a specific antibody (called IgE) present to the food 'allergen'. These antibodies are measurable in blood tests, and food allergy can also be diagnosed by skin prick tests in most cases. Generally, food allergy reactions occur quite rapidly, often in minutes but generally within a maximum of 2 hours.

Food intolerance is a reaction which is not antibody dependent; many of the reactions which come under the heading of intolerance are delayed by hours or even days. The mechanism involved in intolerance is not fully understood and blood or skin tests are not helpful. However by carrying out special food studies on the child (usually in hospital) it is possible to prove that the intolerance exists. Food challenges are ideal for the diagnosis of food intolerance and a positive test result confirms the need for avoidance of the relevant food. Food challenges are unsuitable in children who have had severe allergic reactions, as even minute quantities of the food will provoke the same response. 

As diagnosis of a food allergy or intolerance is complicated it is best for families to be referred to an allergy specialist for confirmation of the problem. If a case of food allergy or intolerance is proved, it may be difficult to find alternatives which are acceptable to the child. Dietitians often work in conjunction with allergists and they are very skilled at helping to find suitable alternatives to the offending food and ensuring a nutritionally sound diet is devised.

If possible, your general practitioner should refer your child to a specialist in allergy or immunology for diagnosis of your child's allergy. Often your recounting of your child's history of reactions will provide enough evidence for diagnosis but confirmation is helpful; it also provides an opportunity to discover whether more than one food is likely to cause an allergic reaction. In many cases children are allergic, not just to foods, but also other allergens including pollens, pets and the house dust mite. Your specialist will be able to assist in diagnosing these other allergies and suggest treatments to prevent symptoms or at least reduce them. Children with asthma or suspected of suffering with asthma will benefit greatly from such consultations and their whole quality of life can improve as a result of such specialist help.

With serious food allergy, confirmation by skin prick tests or blood tests will reassure the child and parents that avoidance is necessary and compensate somewhat for the difficulties in excluding a food from the diet. However there are limitations to how much the allergy tests can show. Unfortunately, there is no direct correlation between the size of the response in the skin prick test or the result of the blood tests to show how severe an allergic response will be. There is also no way of telling how severe the next response will be to the food which caused the last reaction. However, the tendency is, if it was a severe reaction then the next reaction will be at least equally severe and possibly worse.

Once a diagnosis has been made, the hard part starts. At present the best treatment is avoidance of the offending food. New anti-allergic treatments, including vaccines, are being developed but it will be some years before these are likely to become available because of the rigorous safety testing of new drugs. Meanwhile, certain drugs (such as antihistamines) may be used in some cases to try and reduce the allergy symptoms.

Despite careful avoidance of the trigger foods, allergic reactions do sometimes still occur. Severe reactions usually occur due to a combination of circumstances including misunderstanding with caterers as to what a dish contains or to the re-use of oil in which something to which one is allergic to has already been cooked, leaving traces of the allergen to contaminate the dish. With certain foods contamination may occur due to the same production line being for different products. Nuts are often the culprits in these instances. However, if one is properly equipped to deal with an allergic reaction, any accidental consumption of a trigger food may be frightening, but the child will be safer. "Properly equipped" in this instance is Epinephrine (adrenaline) in an automatic injector (Epipen or Anapen). With epinephrine there is enough time to avert the attack and reach a hospital emergency department, where further medication can be administered as required.

Most of the deaths of food-allergic people occur outside the home and mostly due to the late or non-administration of adrenaline. Adrenaline is quickly used up, so any effects will be short lived and a second injection may be required. Two autoinjectors are recommended for this reason. With severely allergic children (and adults) symptoms usually manifest themselves so quickly and clearly that the chance of wrong administration of adrenaline is very small. It may not seem very consoling to have to inject a child if a reaction occurs, but it is life saving. It is also recommended that one goes into hospital following the injection of epinephrine as a late phase allergic reaction may occur. People who are allergic to food and suffer from asthma are at greater risk of anaphylaxis and should therefore be especially carefully monitored and should be given their "reliever" inhaler in addition to adrenaline.

Alcohol potentiates the allergic reaction and may increase the severity and speed of the reaction. Fortunately most children do not drink alcohol, but it is something to consider as they grow-up

What can you as a parent do?

If you or your partner has a history of allergy or you have another child with allergy then strict breastfeeding is best if possible. You may wish to avoid nuts, including peanuts, whilst pregnant and during breast-feeding and ensure that your baby is not fed with any bottles other than special formulas for allergic babies while you are in hospital. It is not advisable for the mother to avoid milk without medical and dietetic advice as this could result in serious nutritional deficiency for mother and baby. If you must stop breast-feeding or are unable to do so then a special non-milk formula may be recommended. If you decide to introduce solid foods before 4 months of age, then you should avoid giving your baby foods that are more likely to trigger allergy (peanuts, egg, cow's milk, nuts, seeds, wheat, fish or shellfish) until after 6 months. When you do introduce these foods, give them one at a time and look for any signs of an allergic reaction.

Even with all these possible precautions there is no guarantee that your child will not be food allergic. Research has shown that the later the introduction of potentially allergenic foods the less severe the reaction is likely to be. There is also no age limit to becoming allergic, it can occur even in old-age. But by making a good effort to reduce allergen exposure reduces the chance of an allergy developing and helps reduce the severity of the allergy.

More information about childhood food allergy is available from the 'Blossom' campaign (via the Allergy UK helpline or on the blossom website).

Make your numbers felt

Join an organisation such as Allergy UK. The more members we have the more impact we can make on food manufacturers to label foods fully and to try to reduce cross-contamination of different products by the use of dedicated production lines.

Every person who is severely allergic should wear an internationally recognised emergency symbol, which ensures that in an emergency, where the cause of collapse is unknown, the necessary information is available to the emergency services. The correct remedy can then be administered and a life saved.

Be prepared to write to manufacturers regarding the need for complete labelling of products, and if an adverse reaction occurs then let them know what happened and why.

Updated 4/2009