Paediatric Allergy Service

What is an allergy?

Most people probably know what allergy is – you touch or eat something, or you take a medicine or get stung, and your body reacts in an abnormal, unpleasant and unhelpful way. Often there is an itchy rash, sometimes there are more severe reactions which are sometimes called anaphylaxis.

Hay fever is very common and is an allergy to grass and/or tree pollen. Other common allergies are to foods (especially milk, egg and nuts), pollen (e.g. hayfever), animal hair, and drugs (e.g. penicillin). Some children with eczema see definite effects from what they eat. Different allergies are seen in different communities and different parts of the world.

In medicine, we recognize that the body has all kinds of ways of responding to these kinds of things, and we only call it allergy if the reaction is driven by the immune system.

The immune system is all the things in your body that are meant for fighting infection, including white cells in your blood, other special cells in your other tissues, different chemicals and antibodies that these cells can make.

Most of the time, you don’t notice your immune system, it just does its job quietly in the background, until it fails to control or stop an infection, or until it overreacts to something that isn’t an infection and causes an allergic reaction. It’s as if it gets confused and thinks that the thing you have just eaten is some sort of infection and starts to fire off all kinds of chemicals and reactions.

If it’s not an allergy, what is it?

Other kinds of reaction can happen that are not caused by the immune system, although they can look pretty similar. People often think they are allergic to something because it makes them feel sick or unwell, but there are other causes such as chemicals in foods or lack of enzymes in the gut or an abnormal gut lining hich are nothing to do with the immune system.

There are different names for these kinds of problem e.g. salicylate sensitivity and lactose intolerance. Coeliac disease is caused by an abnormal immune response to wheat, but this is a different kind of reaction than that seen in allergy.

Some people get rashes or swelling that can look allergic, but it is not because something they have come into contact with or eaten has triggered their immune system. Instead, their immune system has started to misbehave for some other reason, often an infection.

Are there different kinds of allergies?

Parts of the body

Allergic reactions can affect different parts of the body e.g. eyes, mouth, nose, throat, gut, lungs and skin. Ears and other parts of the body can sometimes swell up. Some people get reactions affecting only one or two parts of the body e.g. eyes (allergic conjunctivitis) or the gut (vomiting and/or diarrhoea) but some reactions affect lots of different parts of the body (e.g. swollen lips, vomiting, wheezing and sneezing, all at the same time).

What kind of reaction you have is not always predictable – people who are allergic to nuts, for example, don’t all have the same type of reaction.

Types of reaction

If you could look inside the body and see what was going on during an allergic reaction you might see different things happening in different people. In medicine, we try hard to work out whether a reaction is Type 1 or not.

A Type 1 reaction is usually immediate (or within an hour or two at the most), can be severe, usually involves itching and swelling, and goes away quite quickly (within a few hours). The reason we care about this is that it changes the kinds of tests we can do and it also tells us whether you are at risk of anaphylaxis or not.

See below for other allergy subtypes.

Cow’s Milk

Some people have immediate allergic reactions to milk, with rash, swelling, itching etc. Others have more delayed reactions, especially diarrhoea and abdominal cramps. Some people get a mixture of these. It is thought that immediate and delayed reactions are caused by different processes going on in the body.

Milk allergy usually becomes apparent at a very young age, since baby formula milk is made from cow’s milk, but the diagnosis may be delayed in breastfed babies. Breastfed babies can however still be affected by milk allergy because they are exposed through breast milk to milk proteins consumed by their mothers! Sometimes it is helpful for breastfeeding mums to stop drinking milk and eating foods containing or made from milk.

If you are allergic to milk, you will usually also be allergic to other foods made from milk, including yoghurt, cheese and butter. But some people with a milk allergy can eat cooked foods containing small amounts of milk.

Because milk is an important source of calcium, alternative milk is usually recommended. In young babies (under 6 months) this is usually a specialist infant formula e.g. Nutramigen. In older babies, soya formula may be used (although some people allergic to cow’s milk will also be allergic to soya). Older children may use soya milk that has been fortified with calcium. You can also get soya-based yoghurt and cheese.

Most children with milk allergy will grow out of it. Repeating allergy tests over a year or two can be useful to see if this if likely.

Egg allergy

A common allergy in young children which often goes away as they get older. Many children with egg allergy can eat small amounts of cooked foods containing small amounts of egg, although you should ask your doctor if this is something you can try.

The MMR vaccine (and some others) are made using eggs, so sometimes it may be advised that you don’t get them or that they are given in hospital with extra precautions. Most children with egg allergy, however, can have their MMR at 12 months of age and booster at 3-4yrs as normal.

Latex allergy

Latex comes from natural rubber and is used in a variety of products including:

rubber gloves
rubber balls
shower mats
hot water bottles
carpet backing
balloons.

Some people have instant reactions to latex, others have delayed reactions (usually dermatitis).

Drug allergy

There are various ways in which you can react to a drug you have taken or been given. Sometimes the reaction is actually to do with the intended effect of the medicine e.g. feeling dizzy with blood pressure medicines. Sometimes it is an unintended but inevitable effect of the medicine e.g. diarrhoea with antibiotics. Sometimes symptoms are blamed on the medicine that is probably due to the underlying condition or disease that the medicine was given for e.g. a rash due to a virus infection.

Other reactions are allergic, in the sense described above, with rash, swelling and itching e.g. penicillin. Yet other reactions are not truly allergic but still make it unwise or unsafe to continue the medicine or take it again in the future. Trying to work out what exactly is going on with drug reactions can be tricky.

Bee/wasp allergy

Unlike many other allergies, people who are allergic to bees and/or wasps tend not to have other allergies (or come from families where other allergies or allergic conditions are common).

People are often worried that because someone else in their family has a severe allergy to bee/wasp stings that they themselves will have a severe allergy but unfortunately there is no test to predict whether you are likely to have a severe reaction.

What is anaphylaxis?

Anaphylaxis is a fancy word for a severe allergic reaction. In a severe reaction, you get breathlessness, wheezing, choking, or you may collapse and lose consciousness. You usually don’t see all these things at the same time, although it’s possible.

Severe swelling of lips, eyes, tongue etc can look terrible but is rarely life-threatening so we don’t consider it anaphylaxis without the other things.

These kinds of reaction are unusual but can be life-threatening. We have particular ways of treating these reactions, including adrenaline pens (e.g. EpiPen) but it is better to prevent such reactions ever happening if possible.

Antihistamine, inhalers and adrenaline

There is a range of medications that can be used for allergy. There are medicines that you can apply directly to the affected part of your body e.g. eye drops, nasal sprays and skin creams. There are also inhalers you can use if it’s mainly your lungs that are affected.

There are also medicines you can take by mouth, which tend to work on all parts of your body. Antihistamines are an important group of medicines that work by blocking the effects of an allergic reaction, many of which are due to the chemical histamine (itching, swelling, redness etc). There are different kinds of antihistamines, some can make you sleepy and some can work for the whole day with just one dose. The most commonly used antihistamine is Chlorphenamine, sometimes called Piriton (one of the brand names for it). You can actually buy it over the counter, but children can get it for free on prescription. We often recommend having the liquid rather than the tablets because the liquid is easier to swallow if you have any itching or swelling in your mouth.

People who are at high risk of severe allergic reactions may be prescribed an adrenaline preloaded autoinjector pen. The best-known one is called the Epipen. Hopefully, you will never have to use one of these because with care you might be able to prevent yourself from having a reaction. If you do have a bad reaction, an adrenaline autoinjector (e.g. Epipen) can be lifesaving so it is important to have it available and know when to use it and know how to use it. There are many cases of people having severe reactions and not using their adrenaline pens even though they had one, which could potentially end in tragedy.

Can you grow out of allergy?

Children often grow out of their allergies, especially if they are young when they first develop their allergy. Most children with milk and egg allergy do grow out of their allergy in childhood. But other allergies, e.g. nut allergy, only rarely go away as you get older. It can be hard to predict who will grow out of their allergy and sometimes your allergy can come back again!

If you ever wonder whether or not you are still allergic to something, say, because you have not had a problem in years, we recommend that you discuss with your local allergy service about having repeat testing or a challenge test in the hospital, rather than just trying at home to see for yourself.

Can you cure an allergy?

Immunotherapy is the name for methods of trying to retrain the immune system to not be allergic any more. For some allergies, e.g. milk and egg, you can do this by carefully introducing a small amount of the food (when advised to do so) and then gradually building up the amount given as your body gets more used to it.

This is not something that we do for all allergies as there is a risk of causing reactions.

For moderate to severe bee/wasp allergy, treatment with a course of venom injections is proven to work but is not available everywhere.

For hayfever, Grazax tablets are available that you dissolve under the tongue every day for 4 months before the hay fever season and you may not get any benefit until the following year. These are currently only available through the NHS in Scotland to an individual in particularly severe cases.

Allergy specialists in Cambridge managed to reduce the likelihood of allergic reactions in 21 out of 23 peanut-allergic children with small daily doses of peanut flour over a one year period. A bigger study is now in progress to find out if this treatment has longer-term benefit. There is similar research going on in the United States. So far this treatment can only be offered in research studies.

Why me?

Allergy, asthma, eczema and hayfever often go together and these conditions are more common in some families than others. So your genes are important. But that’s not enough – the following are all important too:

the age you are when your body first comes into contact with the food/drug/etc
the way in which you come into contact with it (on the skin, by eating it, etc)
how much of it there is

Unborn babies in the womb are also being exposed to foods their mothers are eating via the amniotic fluid.

Being allergic to one thing makes you more likely to become allergic to other things, particularly foods of the same type e.g. nuts, pulses (lentils, beans etc), fruit and grains (e.g. wheat and barley).

If your body is regularly coming into contact with something (by touching, eating, etc) then your chance of becoming allergic is much less.

Symptoms and how to deal with them

Allergic reactions can affect different parts of the body e.g. eyes, mouth, nose, throat, gut, lungs and skin. Some reactions involve only one or two parts of the body but some reactions affect lots of different parts of the body (e.g. swollen lips, vomiting, wheezing and sneezing, all at the same time). What kind of reaction you have is not always predictable – people who are allergic to nuts, for example, don’t all have the same type of reaction.

The below reactions are usually considered mild, in the sense that they are unlikely to be life-threatening. But it can be really unpleasant for the affected person and it can be very scary for other people, particularly if your face and eyes become very swollen.

Swelling, redness, and itch e.g. eyes, lips, face and ears. When it’s a food allergy, the mouth is usually affected and you may feel tingling and itch of your lips, mouth or throat.
The typical skin rash looks like nettle rash and is sometimes called hives. The medical term is Urticaria. It is itchy, red and lumpy, often with white bumps in the middle that can look like blisters.
Some people with food allergies feel sick and can vomit. This is good because your body is trying to get rid of the problem food! But you can also get cramps and diarrhoea.
If your nose is affected you may start to sneeze and your nose may stream.

The standard treatment for any of the above symptoms is an antihistamine such as Chlorphenamine. You may find it easier to swallow a liquid antihistamine rather than a tablet, particularly if your lips or mouth are swollen. Often your symptoms will start to improve within 10 minutes, but if they do not or worsen then you may need to take another dose and/or seek further help from a doctor or NHS24.

The following are symptoms of a potentially life-threatening allergic reaction (sometimes called anaphylaxis):

Sudden or increased breathlessness, maybe wheezy
Choking, struggling to breathe
Going pale, cold and clammy
Loss of consciousness or fainting

If you have an adrenaline autoinjector pen, then this would be the time to use it. You should also take an antihistamine, as above, if able. If you have a blue inhaler e.g. Salbutamol and you feel wheezy or chest tightness, you should use it (preferably using a spacer device e.g. Volumatic).

If you are having a severe allergic reaction, phone 999 and say you are having a severe allergic reaction. Wait until the ambulance arrives. Even if you feel better by the time they arrive, your medicines may start to wear off quickly – this is particularly true of adrenaline. The ambulance paramedics have emergency medicines they can use.

If you feel dizzy or faint, it is best to lie down, preferably in the recovery position. If you have breathing difficulties, however, you may find it better to stay sitting up.

How do you test for Allergy?

There are a few different ways of testing for allergy.

Blood tests can be quite good for some kinds of allergy but are not very reliable for babies and it takes a few weeks to get the results.
Skin prick tests can be quite good, and you get a result within 15 minutes, but again are not very reliable for babies.
Patch testing is done by some dermatologists looking for contact dermatitis – the patch is applied to your back and left for 72 hours.

But there are some people where testing doesn’t seem to work properly. It might be because their allergy is restricted to one part of their body e.g. their eyes or nose.

Sometimes there is no obvious reason and the only way to prove the allergy is to do a challenge, where you are intentionally exposed to whatever it is you are allergic to. There is obviously a risk here that you might have a nasty reaction. Sometimes a double-blind test is done, where you are given something (to eat, usually) that you can’t see/taste/feel and which may or may not be what you are allergic to. This is in some ways the only perfect test but is usually only done when symptoms are inconsistent or unusual.

There are some “allergy tests” that are advertised that are not recommended by health professionals on the basis that there is no scientific evidence of their validity e.g. IgG blood tests and hair analysis. Please discuss with your GP or allergy doctor/nurse before paying for any kind of allergy test, on the high street or internet!

What is Skin Prick testing?

Depending on what things you are suspected of being allergic to, you may be offered skin prick testing. You should avoid taking anti-histamine medicines for at least 3 days before the test as this will potentially reduce the usefulness of the test.

An extract of whatever you may be allergic to (a food, pollen, animal hair, house dust mite etc), or sometimes the actual material, is applied to the skin of the forearm. A very short needle is then used to gently prick the extract into the skin. This can be uncomfortable briefly but it does not usually cause bleeding. If you are allergic, an itchy red swelling will appear after 10-15 minutes. Skin prick testing is very safe.

Can’t you just test for everything?

There are two issues here. Firstly, because allergy happens because your body becomes sensitive to specific things (sometimes just one thing, e.g. egg) all allergy tests are very specific. Both blood and skin testing look for allergy to specific foods, animals etc. With blood testing, some mixtures are used e.g. common foods, nuts but you would still want to know which specific thing(s) in that mixture you were allergic to. So there is a very large number of things that can potentially be tested for, and apart from the cost, you would need vast amounts of blood or skin!

Secondly, the tests we have are not perfect. That’s why the “gold standard” test is the double-blinded challenge. Some people get positive test results to things they are clearly not allergic too, others get negative results to things they are clearly allergic to! So the history (what reactions happened when) is sometimes more important than the test results.

Can you grow out of allergy?

Can you cure an allergy?

This is not something that we do for all allergies as there is a risk of causing reactions.

For moderate to severe bee/wasp allergy, treatment with a course of venom injections is proven to work but is not available everywhere.

What is anaphylaxis?

Severe swelling of lips, eyes, tongue etc can look terrible but is rarely life-threatening so we don’t consider it anaphylaxis without the other things.

Antihistamine, inhalers and adrenaline

How to avoid issues at school

There are things you should do to avoid problems at school:

Notify the school about your allergies. It would be a good idea to discuss your allergy symptoms and/or offer a letter from your doctor with details of your allergy/allergies
Do not exchange food with other children
Avoid eating anything if you are unsure of what the ingredients are
Tell the teacher immediately you feel unwell, especially if you have just eaten something (even if you didn’t think it had anything in it you were allergic to)
Wash your hands before and after eating your meals
Consider a medical alert bracelet

Here are some questions you might like to put to your school, with the answers we would expect:

Questions to ask

How does your school manage your allergy/allergies?

Answer:
- I have a daily action plan in place
- I have an emergency action plan in place (You may have both)

They have a sealed and labelled container with your EpiPen and/or piriton secured inside a box with prescription details. It should be checked from time to time to see that the medicines are in date.

Does your teacher know what symptoms to look for if you have an allergic reaction?

Answer: Yes, it has been discussed with him/her, and the teacher has received training to manage symptoms

Has your teacher given the class an awareness talk so that they know what to do to help you or who to call for help should you have an allergic reaction.?

Answer: Yes

Has your school catering department been made aware of your dietary requirements?

Answer: Yes

Does your school ensure the tables in the canteen are wiped clean before and after your lunch?

Answer: Yes

Are you aware that you should not be excluded from school activities because of your allergies?

Answer: Yes

Has your school identified strategies to minimise allergic reactions?

Answer: Yes

If you have been prescribed an adrenaline autoinjector pen, you might like to put the following questions to your school:

Do you have an Adrenaline autoinjector pen available at school?

Answer:
- Primary school – Pen and Piriton (or another antihistamine) kept in a secure cupboard within the school office)
- High School – One pen kept in a bag and one pen with Piriton (or another antihistamine) kept in a secure cupboard in the school office)
This cupboard should not be locked, as this would delay access to emergency medication)

Does your school have a meeting plan when going on school activities to ensure you have a trained person to administer your adrenaline autoinjector pen in an emergency?

Answer: Yes

Does your teacher know how to dispose of the used pen safely?

Answer: Yes – give to paramedic attending the patient

Contact Us

Tel: 01698 366193

Consultant: Dr Adrian Sie
Specialist Nurse: Morag Alexander
Specialist Dietician: Jacqueline Neil
Secretary: Heather Baillie

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