Peanut allergy

Disclaimer: This fact sheet is for education purposes only. Please consult with your doctor or other health professional to make sure this information is right for your child.

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What is peanut allergy?

Peanut allergy is a reaction which occurs soon after exposure to peanuts or peanut products. It is due to IgE allergy antibodies against peanut proteins.

How common is peanut allergy?

Recent research showed that in a Western community about 1 in 200 children (0.5%) had a reaction to peanut by 5 years of age. Overall about 1-2% of the population have a clinical reaction to peanuts. About 3% of children have a positive peanut allergy test (such as a skin prick test) but only 1/3 of these will develop reactions on eating peanuts. The occurrence of peanut allergy in childhood differs greatly in different countries. Australia is a country with a relatively high prevalence of peanut allergy. If your child has a positive allergy test but has never eaten peanut your doctor will determine the chance of developing a reaction if there is exposure to peanut or peanut containing products.

What are the symptoms of peanut allergy?

The majority of allergic reactions to peanut are mild and consist of hives around the mouth where peanut has touched the skin, or more generalised hives on other parts of the body. Another common symptom is abdominal pain and vomiting which occurs soon after eating a peanut product. More sensitive children can develop coughing, wheezing, difficulty breathing or hoarseness of the voice due to an allergic reaction occurring in the airway. In the most severe cases collapse and loss of consciousness can occur. Very rarely, very sensitive individuals have died from the severe allergic reaction known as anaphylaxis.

How is peanut allergy diagnosed?

In most cases the clue to peanut allergy is the start of symptoms soon after exposure to peanut product. The presence of allergy IgE antibodies to peanut can be confirmed by an allergy skin prick test or a blood test (called a RAST test). It is important to realise that not every child with a positive allergy test will develop symptoms on exposure to peanut product and the interpretation of the test should be discussed with your doctor. In some cases it may be necessary to confirm or exclude peanut allergy by performing a peanut food challenge in hospital. Your child's doctor will discuss this with you if he / she feels it is necessary.

How do I avoid exposing my child to peanuts?

Peanuts are found in foods we don't always expect them to be in. It pays to know where to look. It is important to use common sense and read food labels carefully.

Avoid foods that contain any of these ingredients:

  • Peanuts, ground nuts, beer nuts, monkey nuts.
  • Peanut oil - cold pressed, expressed, or expelled (note - Arachis oil is peanut oil).
    Highly refined peanut oil is unlikely to cause a reaction in those with a peanut allergy.
  • All peanut products eg peanut butter.
  • Crushed / ground peanut - in sauces or coating on food (cakes, buns, ice-cream), satay sauce, peanut sauce.

Where possible check labels on the following foods that could contain peanut products as an ingredient:

CakeKebabs

Hydrolysed or textured vegetable protein
(HVP & TVP, usually soy)

BiscuitsSalad dressing
CrackersSoupsChocolates
PastriesSpaghetti saucesHealth bars, eg muesli bars
Chinese mealsThai dishesIce creams
Ethnic cookingTurkish delightMarzipan
Indonesian dishesBreakfast cerealsNougat

Is peanut oil a risk?

The problem with peanut allergy is the protein but not the oil (fat) in the peanut. In small studies refined peanut oils have been shown to be safe. Cold pressed peanut oil does contain peanut protein and should be avoided. Unfortunately it is often difficult to guarantee that the oil is sufficiently refined to remove all traces of peanut protein. Avoidance of peanut oil is often advised particularly for people who have had the more severe life threatening reactions.

What about foods with a label that says "may contain traces of peanuts"?

Many foods carry a warning on the label "may contain traces of peanuts". This usually indicates that the food is made in a facility that also makes a food containing peanuts, however the food may not contain peanut. Discuss what to do about these foods with your doctor.

Does my child need to avoid other types of nuts?

Often children may have a reaction to a number of different types of nuts. Different nuts are also often checked when doing skin prick tests. Your doctor may advise your child to avoid all types of nuts depending on your child's test results, type of reaction and family history. It is important to discuss this with your child's doctor. Contamination may occur within processing plants where different types of nuts are processed. Avoidance of all nuts is usually the safest line of action.

What is an EpiPen?

EpiPen is an emergency device which injects a dose of adrenaline into the muscle just under the skin. It is used to treat severe reactions to peanut product. The drug adrenaline reverses the severe allergic reaction and can be lifesaving. Anapen is another brand of automatic adrenaline injector.

Should my child carry an EpiPen?

All allergists agree that children who have had a serious reaction to peanut with involvement of the breathing passages should have an EpiPen. The need for other children to have an Epipen depends on a number of factors which should be discussed with your doctor. If you have an EpiPen it is very important that you understand how to use it and that you have a written Anaphylaxis Action Plan provided by your doctor.

Can my child grow out of peanut allergy?

In most children (80%) with peanut allergy under 5 years of age, the allergy will continue into later childhood. However 20% of children do grow out of their allergy. Those children who have had more severe allergic reactions with breathing problems are much less likely to outgrow their allergy than children with milder reactions. Your doctor can sometimes determine whether the peanut allergy is still present by monitoring the allergy tests every 12 months or so.

Can peanut allergy return after my child has grown out of it?

In nearly all cases once a child has grown out of peanut allergy it does not come back. There are rare cases in which the allergy has returned. It is thought that the allergy may be more likely to return if peanuts and peanut products continue to be avoided after the child has grown out of the allergy. For this reason your doctor may advise your child to consume some peanut products several times a week.

Is my child likely to have a severe reaction from casual contact with peanut product on benches, other children's hands or by smelling peanuts?

No. Severe reactions from casual contact are extremely rare. Recent studies have shown that placing peanut butter on the skin did not cause any severe reactions in a group of peanut allergic children.

Can I prevent peanut allergy in my future children?

There are no methods which can guarantee a child will not develop peanut allergy. There is no evidence that avoiding peanuts and peanut products in pregnancy or in the diet of lactating mothers prevents peanut allergy in their babies. There is some evidence that suggests that skin creams which contain peanut product may promote sensitisation. Recent publications have suggested that early introduction of peanut containing foods in infancy might even protect against the development of peanut allergy.

Where can I find more information on the Internet?

  • The Australian Society of Clinical Immunology and Allergy (ASCIA) website contains useful information on food allergy written by Australian specialists (www.allergy.org.au).
  • The patient support group Anaphylaxis Australia offers valuable updates and tips for dealing with food allergies (www.allergyfacts.org.au).

Remember

  • Read food labels carefully and be aware of unlabelled foods that might contain peanut products.
  • If you have an EpiPen it is very important that you understand how to use it and that you have a written Anaphylaxis Action Plan provided by your doctor.

Written by the Department of Allergy, Immunology and Infectious diseases The Children's Hospital at Westmead.

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