The Peanut Allergy Clinic is a specialist private allergy service at Southampton Children’s Hospital.
An allergy occurs when the body’s immune system reacts to something which should be harmless- like grass pollen, cats, or peanuts etc. When this occurs we often see classical responses which help us identify that someone has had an allergic reaction. We can further confirm that an allergic reaction has occurred by arranging allergy testing.
When someone has had an allergic reaction, they should be assessed by a qualified healthcare professional. An allergy focused history should be taken to determine what has occurred and how likely a diagnosis of allergy is.
After a history of events has been taken, the possible IgE allergy can then be confirmed with allergy testing. Allergy testing should not be done in isolation because all tests have their flaws. Allergy tests can be positive and yet a person can tell us they can eat that food without issue – this is called a false positive. They can also be falsely negative when someone is clearly reacting to a food. It is vital therefore that testing is undertaken by someone qualified and trained in allergic disease.
The most common ways of allergy testing are with a blood test or a skin prick test. If there is doubt about a diagnosis, a hospital food challenge may be arranged. This is when someone comes into hospital for half a day and is given increasing amounts of the food they are testing. They are monitored throughout in a safe environment to see if any reaction occurs.
a small amount of blood may be taken to check for the IgE to the allergen they are suspicious of – for example, an IgE to peanut is taken if we are investigating a possible peanut allergy. If the test is >0.35, we say that it is positive. The test goes up to >100 but it is important to be aware, that the value of the blood test is of no use in predicting how likely it is that anaphylaxis may occur. Anyone with an IgE mediated food allergy, regardless of the size of the blood test, is always at risk of anaphylaxis occurring.
the quickest way to confirm an allergy is with an allergy skin prick test. This can be done on children of any age, but it is important to stop all antihistamine medications for at least 5 days before the test as this can interfere with the results. Despite the name, skin prick tests are not painful and many young children tolerate it extremely well. A skin prick test can be carried out to a range of potential allergens and the results will be available within 15-20 minutes. As with blood tests, we cannot predict the likelihood of anaphylaxis based on the size of a test result.
Allergy and Intolerance Testing’ is often widely advertised and it is vital to ensure that the correct test is chosen, preferably after a consultation with a qualified physician. Allergy tests which are performed on samples of hair, vega testing, kinesiology or blood tests that are taken to measure IgE are inaccurate and are not valid forms of confirming allergy. The British Society of Allergy and Clinical Immunology have produced a useful information sheet about alternative tests which can be found here;
These reactions can be much harder to diagnose than IgE mediated reactions as currently, there is no test which has been diagnosed to them. Non IgE allergies commonly present within the first few months of life and tend to have mainly gastrointestinal symptoms. They can cause reflux, vomiting, explosive diarrhoea, soft stool constipation (children seem constipated and strain but when their bowels are open, the stool is soft), redness around the anus and abdominal pain. Babies with these allergies tend to be very unsettled and cry for long periods of time due to the level of inflammation that is occurring in their gut due to constant exposure of an allergen (food they are allergic to). These allergies can also cause nasal congestion (in associated with gut symptoms) and unmanageable eczema. If these babies have severe disease, they may refuse feeds and their height and weight may be affected.
The commonest foods which cause Non IgE Mediated allergies are milk, soya, wheat and egg. Other foods can also trigger symptoms.
Symptoms can occur 2-72 hours after exposure to the food and it may take several days or longer for things to improve.
The only way we currently have of diagnosing this condition is by removing the suspected food for 2-4 weeks and seeing that things get better. If they do, to confirm that this food was definitely causing a problem, a small amount of the food needs to be given again. If the symptoms reoccur, we know for sure that they are reacting and a diagnosis is made. Hopefully in the future, a test will become available to make this diagnosis easier.
There are a few other recognised conditions which can occur to food.
Eosinophilic Oesophagitis – this condition can affect individuals of any age and its prevalence is increasing. It commonly causes indigestion, chest pains, vomiting and food can get stuck. It is diagnosed by a test called a gastroscopy. A camera will be inserted into the mouth and down the food pipe into the stomach. Biopsies are taken at multiple levels to check for raised eosoinophils. Some individuals will find that different foods trigger their symptoms.
Food Protein Induced Enterocolitis Syndrome FPIES – Individuals with this allergy tend to have profuse vomiting which occurs after exposure to the food they are allergic to 1-4 hours later. Some people will also have diarrhoea with it. Those with an FPIES reaction tend to look very unwell, turn pale and can become floppy. It is not unusual that they end up in hospital after exposure to the food. Currently no test exists to diagnose this condition and it can take repeated exposures and reactions to occur before someone realises the cause.
Some individuals will have mixed IgE and Non IgE allergies and it is important they are assessed and managed by an allergy team.
Many families who already have a child with an allergy are desperate to know if they can prevent it from occurring again. Unfortunately, there is currently nothing specific that we can recommend during pregnancy or the early months which will prevent an allergy from forming. Removing foods or including foods in your pregnancy or breast feeding diet will not affect your child’s risk of developing a food allergy. Whilst there is much research occurring into the use of probiotics, there is currently not sufficient evidence to suggest that it will prevent an allergy from forming. However, we are now aware of the importance of early introduction of some foods into an infant’s diet which may help prevent a food allergy from occurring.
For children whose siblings have allergy but they themselves have no food allergies or eczema, then weaning advice follows the traditional route- ie, when your child is showing signs of being ready to wean at around six months (and not before 4 months), they should have foods introduced in the normal way, starting with vegetables, fruit and then other foods. Screening siblings for a food allergy is not routinely recommended due to the limitations of allergy tests and the delay this may cause to weaning.
If your baby has eczema or already has a food allergy, then they may be at increased risk of food allergies developing. To help prevent this, we recommend considering introducing food from 4 months of age. It is recommended that you begin in the usual way with pureed vegetables and fruit but there should be a concerted effort to introduce eggs and peanuts early. Eggs should ideally be given before the age of 7 months and peanuts (which should be given in an age appropriate form to prevent choking) before the age of 11 months. Giving these foods regularly, ideally 3 times a week until the age of 5 years, has been shown in large studies to significantly prevent an allergy developing.
It is important to remember that sometimes despite our best efforts, allergies will still form. Therefore, if you think your child is reacting to a food (even if they have eaten it successfully before), then you should stop giving it and seek medical advice. 10% of children eating peanuts regularly still developed an allergy in the Learning Early about Peanuts Study.
After you have introduced your baby to egg and peanuts, it is recommended that other allergens (foods which can cause allergic reactions) are introduced. These foods include tree nuts, seeds, fish, shellfish, wheat and cow’s milk.
Whilst allergic reactions can occur in weaning infants, anaphylaxis is uncommon – affecting 1-2 per 1000 babies. Deaths from anaphylaxis in all age groups is rare and in the UK there are thankfully only 20-30 deaths from all causes of anaphylaxis (drug reactions, venom allergies, food allergies, spontaneous reactions). Every day activities like being in a car are far more risky that weaning your child but we fully recognise the anxiety that many families feel. You should consult your GP or Health Visitor if you feel you need any support.
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Immunotherapy can be considered for all children with an IgE mediated food allergy and there are very few children who cannot undertake treatment. If a child has asthma which is not controlled then we will need to improve this before treatment can commence. Additionally, if a child has Eosinophilic Oesophagitis, then immunotherapy is not likely to be suitable. Dr Helen and Dr Mich will make a careful assessment in clinic and confirm that your child is likely to benefit and be safe with treatment.
The treatment comes as a capsule which contains peanut protein. The capsules are carefully opened and mixed with a cold pudding like a yoghurt or custard. Children are initially started on a very small amount of peanut protein which is given in a supervised clinic environment. Our clinics are always well staffed, and we have highly qualified staff available to monitor your child at all times. Once your child has tolerated their first ‘dose’ in clinic, they go home and continue to have this dose daily for 2 weeks. We then see you all in clinic again after 2 weeks to give the next dose up.
Our treatment programme is for 2 years. Children will visit us at Southampton Children’s Hospital every 2 weeks for the first 6 months. After this, children will visit every 3 months for the next 6 months. After the first year, children are swapped from the licenced medication to peanut M&Ms and follow ups are done virtually for another year. It is important to understand that we recommend peanuts are kept in the diet daily even at the end of our two-year programme to ensure that tolerance is maintained.
By the end of the treatment programme individuals are able to tolerate 300mg peanuts -this equate to one to two peanuts. After the first year on the licensed medication we will transfer your child to peanut M&Ms to keep costs down. They will safely be able to eat two peanuts a day but many individuals in the study were able to have much higher amounts of peanut than this without a reaction.
Undertaking immunotherapy is a commitment which the whole family needs to be on board with as there are frequent appointments for the first six months. However, we all recognise that life needs to continue despite active treatment and therefore, many of our families will still go on holiday during the treatment programme and we can make arrangements with you for treatment to continue.
If you would have any questions or would like more information, please complete our short form and we will be in touch as soon as possible.
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A specialist peanut allergy clinic for children aged 0-17yrs undergoing peanut immunotherapy.