Foods can cause a wide variety of reactions in children. A food allergy can be life threatening in some rare cases but most reactions are less severe. Foods are often blamed when they are not the cause of the problem, so it is important to get any illness or reaction checked by a doctor to be sure of the cause.

Food allergies are not common (probably around five percent of people have a mild food allergy, and severe food allergies are rare), but many people think that they are allergic to foods - some research has reported that up to 20 percent of people are limiting the foods that they eat because they think they are allergic to a food.

Food reactions are more common in young children and most disappear as the child gets older. If one or more foods cannot be eaten by a child, it is important to be sure the child is still getting a healthy diet.

If a child has had a severe reaction to a particular food (especially one involving breathing difficulty or collapse) it is most important that the food is not given to the child again unless the child is being observed by a doctor.

Types of reactions to food

• Food allergy is an immediate reaction to food. This is a reaction of the body's immune system, which happens quickly after the food is eaten and can be very severe, but is usually not severe.
• Food intolerance is more common but usually less severe. It involves reactions to foods that are not to do with the immune system. They can happen up to 2 days after the food is eaten. Many chemicals in food may be involved.
• Reactions to cows' milk may be either food allergy or food intolerance.
• Effects on behaviour. Whether some foods cause reactions such as hyperactivity or chronic fatigue is controversial. Some people are certain that foos have a major impact on how they feel, but there is little evidence that this is the case for most children who have ADD or ADHD.
• Food poisoning is a reaction to a poison in foods, often from bacteria. This is not covered in this topic.

What is food allergy?
Food allergy is a reaction by the immune system to a specific protein in food. It happens mainly in babies and children. There are usually other people in the family who have allergies (food allergies, asthma, hay fever or eczema). The reaction happens quickly, usually within 30 minutes and always within two hours. Only a few foods are involved in most cases. Peanuts, cows' milk, and eggs are the most common, but for some people fish and shellfish, soy and wheat may also cause allergic reactions.

A particular child may be allergic to only one or two of these, but may be sensitive to very small amounts of that food.

Children usually grow out of allergies in a few years, but peanut and fish allergies more often do not go away.

Reactions

• Local reactions can occur, such as a red rash around the mouth where the food has touched the skin.
• General reactions include skin rashes on other parts of the body, hives, swellings, vomiting, wheezing or other breathing problems, or in rare cases, collapse.
• If a child has a severe reaction to a food (anaphylaxis) the child needs urgent medical assessment and treatment. Use the child's EpiPen if available and call the Emergency Service (000 in Australia).

What you can do

• If you think your child might have a food allergy, see your doctor to be sure.
• It may be clear from what happened that it is a food allergy, or sometimes skin tests or blood tests are done.
• The food that is thought to be causing the allergy will need to be taken out of the child's diet.
• Other foods that often cause allergy may also need to be avoided by the child.
• Make sure your child still gets a good balanced diet - if you are unsure about this ask a nutritionist or dietician.
• After a year or two the problem foods may be tried again, but only with the doctor's supervision. If your child has had a very severe reaction to a food this should only be done in a hospital.
• Ongoing severe allergies (eg to peanuts) can be a real problem. These children may need to carry adrenalin for use in an emergency, and special care may be needed at childcare, preschool and school to protect the child.

Reducing the risk of food allergy
The tendency to develop allergies (atopy) is inherited so it tends to run in families. If there is a strong history of food allergies in the family, talk to your doctor or paediatrician to discuss what might reduce the risk of your child having food allergies. Avoiding foods during pregnancy does not appear to lower the risk of food allergies.

Breastfeeding
Breastfeeding is recommended because of many beneficial effects. Aim for exclusive breastfeeding for around six months, and continued breastfeeding for the first year with other foods. Avoiding certain foods while breastfeeding does not appear to reduce the risks of developing food allergies.

If breastfeeding is not possible
Special formulas (partially hydrolysed formulas) may be useful in reducing the risks of allergies in babies where there is a strong family history of allergies, but they should not be used if a baby is known to have a cow's milk allergy. Using soy formulas or goat's milk formulas instead of cow's milk based formulas does not reduce the risk of developing food allergies.

Introduction of solids if there is a high risk of allergies
There is no evidence that delayed introduction of highly allergenic solids decreases the risk of the child developing a food allergy. Follow the general guidelines for introduction of solids.

• Introduce solid foods around six months of age. Watch for signs that your baby is ready to start eating solid foods - do not delay the in - do not delay the introduction of solid foods.
• Do not delay the introduction of cow's milk, soy, wheat, egg and fish - introduce them into your child's diet at the normal time for introduction of solids.
• If there is a strong family history of nut allergy, introduction of nuts after 2 to 4 years of age may be recommended. Discuss this with your doctor.
• Watch for signs of food allergies and if you think your child may be reacting to a food, discuss this with your doctor.

Symptoms of food allergy include

• Onset of a red raised and itchy skin rash following exposure to a new food. This may be associated with noisy breathing, vomiting or loose stools.
• Severe eczema, poor growth.
• Many foods that can trigger allergic reactions are also important parts of a healthy diet. They should not be excluded from a child's diet unless there is a clear reason for doing this. For example, it is reasonable to exclude peanuts if there is a family history of peanut allergy, but cow's milk should only be avoided if your child is not tolerating it.