Dr David answers your questions on allergies and intolerances

Dr David regularly joins us in the Coffeehouse to answer your health queries, offering an opportunity to get informal advice and expert answers on the issues that matter to you.

In the page below you can read a summary of the web chat Dr David took part in on food allergies and intolerances.

If you're concerned that your child may have an allergy or intolerance you might like to take a look at the Q&A below, where Dr David answers questions on issues such as milk, wheat and gluten intolerance, peanut allergies and eczema. You can also read the full chat in our Coffee House archive.

Confirming an allergy/seeing a specialist

Q: I have a 5 year old son who has a severe milk, egg and tree nut allergy. He isn't showing any signs of outgrowing his allergies, if anything they seem to be getting worse. We currently see a paediatrician at our local hospital once a year but was wondering if we should be seeing an allergy specialist. We don't seem to be getting any continuity of care as it's a different registrar taking the consultants clinic every time we go. He hasn't had any skin prick or blood tests, we have just worked out ourselves what he is allergic to. We just feel we're left to get on with it, really. I also hear of trials for cures for food allergies - are these through the NHS or private clinics? How would I go about getting my son onto a trial?

A: Your son needs to see an allergy specialist and should have skin prick tests or blood tests to confirm the allergy. For example, his reaction to milk may have been when he was a baby and you've avoided milk since then and are assuming he's still allergic. He might be, but the majority of children grow out of egg and milk allergies by six. Tests can indicate if there's a chance they have grown out of it, meaning it's worth finding out in hospital where it's safe and controlled.

Being told you no longer have a food allergy makes a huge difference to your life so it's worth finding out. If your son has had reactions in the last three months to these foods and you're sure it is those foods, then it's less likely he's grown out of his allergy. It's important to get the tests and have the right people interpreting them. Tests you buy online or in homeopathic shops are NOT validated and should never be 100% trusted. This link might help: British Society for Allergy and Clinical Immunology.

Regarding trials for cures, this is still in the experimental stage and not offered as a treatment anywhere. But first of all you do need to confirm the allergy is indeed still present.

Q: My daughter is 6 years old, and suffers from mild to severe tummy cramps. She has had this since she was a toddler and only recently came off lactulose for constipation, but the tummy aches are persistent. She seems to get a tummy ache before she needs to do a poo. We have seen our GP and at first he thought it was associated with anxiety but I have pushed for more help in finding out whether it is physical or just psychological. We are now keeping a food/poo/anxiety diary so that the paediatrician can make a more informed decision about blood tests for her. My question is do blood tests reveal intolerance (we suspect she might be intolerant to egg) If our food diary reveals it may be a food intolerance, can that be proven with any kind of test?

A: There are lots of reasons why children get tummy aches and I'm glad you are seeing a paediatrician. Keeping a food diary is helpful. But there's no real test for food intolerance, rather the advice is to go on a six week diet completely avoiding that food and seeing if symptoms go away, then reintroducing that food slowly to see if problems come back. Try your daughter off egg for a month (check all food labels) and see if that helps.

Q: I went to the GP today and they are going to try and take blood from my 16 month old son for allergy testing. Do they take blood and if it reacts badly is that confirmation he has allergies? Then do you get further testing or is that it?

A: Blood tests can be useful but don't relate to the extent of an allergy; they can support it in conjunction with a history of a reaction. For example, if a child ate peanut with egg and had a reaction, it might not be clear what caused it but if a doctor carries out blood tests that might provide a clearer indicator. Blood tests on their own with no history of allergies aren't helpful which is why one shouldn't just do a blanket of tests.

A positive test suggests "sensitisation" which means that a certain food has resulted in an abnormal immune response - antibodies have been made against that food protein. It doesn't mean that child will have an allergic reaction as you can be sensitised but eat the food no problem, and in that situation you don't need to stop eating it. Sorry, it's a bit complicated but my point is nothing is 'cut and dried'. A very high test is perhaps more suggestive of allergy but never 100%. A very low test is suggestive that a child may not be allergic but even if the test says '0', one can't be sure as maybe that's because the child has never been exposed to that food, and sensitisation might occur leading to allergy after a first exposure.

Often young children appear to have been exposed to the food from blood tests yet the parents don't remember them eating it, because they've been exposed through mum eating it in pregnancy, in breast milk or perhaps from touching it or breathing it in if that food was in small particle form, eg milk powder etc. A skin prick test will give similar information. With blood tests, you can't equate the level to the risk of anaphylaxis so we don't suggest it and it doesn't influence our prescription of an adrenaline pen. The history of reactions or if child has asthma is more important.

Q: My son is six months old. Briefly he had severe silent reflux as a baby and this was mainly caused by a lactose intolerance and this has 90% cleared up since his formula was changed to a lactose free variety. So far he has also reacted to soya.Having suffered with allergies myself all my life I do not believe in the "try it and see what happens" system suggested by most doctors and would like my child tested properly asap. But when I asked my doctor he simply skirted around the issue saying there is no point testing until at least five years of age as babies can give false readings due to their immune system being underdeveloped.

Can you tell me if this is actually true? And the minimum age I can insist on a referral? At the moment I am weaning but avoiding dairy due to the lactose problem. I have also so far avoided wheat and the other main groups that can cause reactions but do not want to restrict my son's diet unnecessarily.

A: You need to see a paediatrician, especially one with knowledge of allergies. Lactose intolerance is not an allergy and maybe his symptoms are due to a milk allergy rather than a lactose intolerance. I wouldn't avoid foods without symptoms, just introduce small amounts at a time and on their own so you know which foods are problematic.

Wheat allergy is very rare; wheat intolerance is more common but symptoms are rarely too severe so your child should be OK. With your past history you might more reasonably want to try things with guidance so request a referral, even a dietitian would be a help. Limiting your son's diet might affect his growth and that risk alone warrants a referral. Babies can be tested for allergies - that advice about waiting for five years is nonsense! This link might help: British Society for Allergy and Clinical Immunology.

Milk/lactose intolerance

Q: Is it only lactose in milk that people are intolerant too or can it be other things?

A: Intolerance to cows milk protein is more common than the lactose. Lactose intolerance results in explosive watery diarrhoea, bloated tummy and tummy pain. Intolerance to protein results in varied bowel habits including constipation, eczema, poor weight gain or vomiting.

Q: My son is 15 months old and has been allergic to cows milk protein since he was born. He went onto Neocate at around 6 weeks old and has had a dairy free diet since then. He is also allergic to eggs and tomatoes. We visited the dietitian last week who suggested a gradual reintroduction of milk into his diet. She suggested mixing one ounce of cows milk into his 7oz neocate and see how he does. We started this on Friday and he didn't have any adverse reactions. However, since then he has become very constipated, developed a cough and a runny nose, his skin has gone quite dry and two small patches of eczema have appeared on the back of his knees, although these are quite mild. Could these symptoms be related to the milk?

A: It sounds like he's developing intolerance symptoms so it might be worth stopping and then trying again in six months. The good thing is he's now having only mild reactions so if he has milk by mistake he won't have a severe reaction which is worth knowing. Keep him off it and discuss this issue with the dietitian when next see them.

Q: I just wanted to know if my son will outgrow milk intolerance. He is eight months old and seems to be doing well, putting on weight and not being sick anymore. I do give him cows milk yogurts and he isn't sick afterwards so would it be OK to switch his milk from lactose free to ordinary now?

A: The vast majority of children will grow out of their intolerance, or at least start tolerating certain amounts of cows milk. If your child is OK with yogurts that's a sign things are getting better. He might not tolerate full bottles yet, but I don't know your little one's history regarding how his diagnosis was made. I would build up slowly with the cows milk and if symptoms come back then drop back to what he was tolerating before and review every 3-6 months.

Q: My son was diagnosed lactose intolerant at 10 weeks old and put onto lactose free formula. He has been doing well on formula apart from the constipation! How and when can we determine whether the intolerance is transient or permanent? He is 22 weeks now and nearlly ready for weaning.

A: Permanent (ie congenital) lactose intolerance is very rare. There is no real test to confirm intolerance except by testing stool samples while they are actually on lactose. I'd suggest introducing small amounts of dairy food/milk while weaning and see how your son gets on. If symptoms come back you know there's a problem. It's worth testing him as avoiding all diary is hard work. Lactose intolerance isn't an allergy so he won't get reactions like swelling, itchy rash or breathing problems from lactose which tends to cause more tummy problems like diarrhoea, bloating and abdominal pain.

Reactions in breastfed babies

Q: My daughter is breastfed. Whenever I have eaten either prawns or egg, she comes out in a rash after she's had a feed and then has very smelly and more frequent poos. Does this mean she is intolerant to these foods? Should I avoid these foods in solid forms as she is currently being weaned? I no longer have them in my diet.

A: She might be. What sort of rash does she get - is it itchy, blotchy and like nettle rash or eczema like? Have you eaten egg or prawns other times and there's been no rash? Has she got this rash when you haven't eaten these foods? There's no accurate test. Certainly egg is the second commonest food children are allergic too, while prawns are also a food they can be allergic too.

Her reactions are mild and if she's otherwise healthy, with no asthma and no family history of food allergy, I suggest when weaning try other foods first and then perhaps when she's one or so try a bit of egg, perhaps scrambled etc. Often kids don't like egg anyway. Try a small amount and if there's no reaction after 20 minutes, increase in small amounts. To be extra cautious, try with a food where the egg is cooked first, such as a cake. Don't try with any other food so you know if she gets a reaction it must be egg. If she still gets a reaction I'd see your GP and request a review by an allergy doctor. Prawns, I'd wait a bit longer - quiet an extravagant food for weaning!

Gluten/wheat intolerance

Q: My son is seven months old. I tried him on some toast and a few hives came up so our GP said to try him again on the toast a few days later. We did this and his neck and shoulders were covered in clumps of hives. Could this be a reaction to gluten or more likely wheat or both? He is seeing a dermatologist next week as he has eczema and our GP said to mention it to them. Will they test at this age or just tell us to cut wheat/gluten out of his diet?

A: We rarely see gluten allergies - rather a problem with gluten manifests as coeliac disease, and you don't get hives soon after eating it. A wheat allergy is a possibility. Speak to your doctor and discuss tests - a skin prick or blood test. Are you sure there was nothing else on that toast that might have caused it? If the tests are inconclusive it might be worth retrying a small amount in six months but have some oral antihistamine at home.

Intolerance to other foods

Q: I have 2 and a half year old twins and was wondering what to do about peanuts. What I mean is do you drive to your nearest A&E if you've given your child peanuts just in case? What age do you try, and what do you start with, peanut butter? I am really worried about this nut thing ...

A: I'm not clear why you are worried. Do you have a family history of a food allergy or do your children have other food allergies? If they have allergies to other foods then I'd seek advice on giving your child peanuts as much depends on what allergies your child has and what reactions they've had. If there's no past history then they should be fine to try, initially small amounts of peanut butter perhaps. If you think there are reasons to make your children more at risk of a reaction than the average child, speak to your GP first.

Q: When weaning I gave my child fish which caused no problem at around eight months. A couple of months later he had fish and was then sick a couple of hours later which happened a couple of times. I waited another year before trying again but this time my son was violently sick every ten minutes for six hours. My child is now four and the health visitor has suggested trying a different fish. Should I be referred for tests?

A: Tests might not be helpful as your child is vomiting but not suffering with other intolerance symptoms. It's been a while since you tried your son on fish so it might be worth trying again. Children are often intolerant/allergic to one type of fish but OK with others - eg they might not cope with white fish but may be OK with salmon or tuna. Try small amounts in your child's diet and see how he gets on. Only try one fish at a time and build up how much they have slowly to see if your child tolerates more. But by all means get tested if vomiting and additional symptoms continue.

Q: My little boy is 15 months old. Due to his big brother having an egg and peanut allergy we held off from giving him egg until he was about 13 months. Recently he has started getting eczema (also something his big bro has) and I'm wondering whether the egg could have triggered it? It almost seems too much of a coincidence that the eczema appeared when he started eating egg?

A: It's possible. What you do next depends on how much he likes egg and how severe his eczema is. You could stop egg for a time and see if skin clears up (with standard skin creams). Then reintroduce the egg again to confirm it is the egg causing the problem. Try again every six months and you may find he's OK with cooked egg rather than more raw types.

Q: My daughter comes up in spots only around her mouth when she eats strawberries. They then become like sores and scab over. I wondered if this is something she will grow out of as she gets this reaction even if she drinks something with strawberry in it or anything that contains it. She's three and a half.

A: When the rash comes back I suggest getting your GP to have a look at it. What you are describing seems a little unusual, especially if the rash is not itchy. If it only appears with strawberries and comes on quickly after eating it may be associated and so worth avoiding but re challenge every six months. Sometimes children get local reactions to certain fruits, but if that fruit has been cooked, or sometimes just blended into a smoothie, symptoms are better. See your GP and get someone to have a look at the rash in first instance.

Q: My son is two and he loves tomatoes but they disagree with him. He gets a sore bum and mouth if he eats them. Could eating them cause any internal damage and will he grow out of this reaction? We find it very hard to find foods that don't contain tomatoes.

A: This isn't an allergy - I'd discuss the problem with your GP. It's very unlikely to cause internal damage, especially if your son is OK otherwise. Perhaps reduce the tomato in your son's diet rather then completely eliminate it. True, it's hard to eliminate all tomato but if some gets into his diet now and again it's unlikely to cause much damage so on balance it might be better to live with the odd reaction rather than making the effort to completely avoid tomato in your son's diet.

Eczema

Q: My nine month old daughter has eczema all over her body. She normally has little patches on her face or on her belly but has recently developed it all over her body. I was wondering if something she is eating is triggering it? Is eczema associated with some food allergies?

A: Eczema can be related to food allergies but MOST aren't. The first thing to do is to make sure you're using the right creams for the condition. If there's some association with types of food it may take up to 24 hours after eating that food to see - they try avoiding that food. If there's no clear association, and eczema gets better with treatment, I would watch and see. I'd seek advice before restricting your child's diet too much.

Q: My son is 19 months and has eczema quite badly. Very often it will flare up so badly he says it burns and no matter how much ointment and hydrocortisone cream I put on it won't go down. I have come to my own conclusion that it must be an allergy triggering it but do not have a clue as to what it may be. His bedroom is hoovered, dusted and cleaned every other day and even his mattress is hoovered and cleaned on a regular basis.

A: Tests often don't help in finding out what's causing eczema. Lots of children have a test, and results aren't entirely normal, yet they're able to eat foods with no adverse reaction. With a proper allergy you have a reaction normally within minutes to an hour. So many factors play a part in eczema that abnormal tests don't always correlate with eczema. Seek advice to ensure your child is on the correct treatment for it. Hydrocortisone is a very mild steroid so your child may need a stronger one which is very safe for a short period. If the medication is correct, and there's some correlation to flare ups with food eaten (usually flare ups occur within 24 hours of eating the food) then tests might help but even then you can only can be sure if you eliminate that food from your child's diet for 4-6 weeks and see the effect on eczema - so could try that without the test. Then, if that seems to help, reintroduce the food slowly to see if comes back, but you must do this in tandem with proper skin treatment.

Allergies and travelling

Q: Does anybody have any experience of taking epipens onto a flight? I know I should contact the airline etc, but am thinking of booking our first flight with my daughter after she was diagnosed with severe nut allergy two years ago. I wonder if I'll need a doctor's letter to be able to take the epipens into the cabin as obviously they have to come with us in hand luggage. I've only had the nerve to take her on the ferry to France over the last 2 years, but after no further allergic reactions due to avoidance, I now feel strong enough to take the plunge and go further afield.

A: Check with the airline. Play safe and get a letter from your doctor as the man at the terminal may be a 'jobsworth' and the last thing you want is to be told you can't take the epipen in hand luggage. It's also worth letting your airline know about the allergy, so you can be aware of the food they serve on board.

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