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Ask the Experts: Dr Jose Costa on allergies in children

Ask the Experts: Dr Jose Costa on allergies in children

We were very fortunate to have some time recently with Dr Jośe Maia Costa, who is a Consultant Paediatrician, fellow of the Royal College of Paediatrics and Healthcare and a member of the Core Group at the British Society of Allergy and Clinical Immunology, Standards of the Care Committee. In addition, Dr Costa has also been appointed as the Honorary Clinical Lecturer in Allergy at Warwick Medical School and is currently leading the Paediatric Allergy Service at the University Hospitals of Coventry and Warwickshire.  

I can’t think of anyone better to talk about allergies and the different issues that all parents are dealing with, particularly at this moment in time.

Yes, well it’s an on-going issue, but the problem about allergies is that it’s under-recognised and, on the whole, people tend to find information hard to come by. This is particularly the case in primary care and the main issue we see is that there is so much contradictory information between the Health Visitors, GPs and whoever else. And the main problem with this is that allergy training in this country is very, very limited, as GP trainees just don’t receive it. Most of the doctors in the country don’t have even one month of work with allergies so they are completely unaware, which is very sad. I was speaking to someone I’m working with recently and I sent her a few documents because we are writing a letter to Matt Hancock and she didn’t even realise that there is a massive document called ‘Allergy, the Unmapped Need’ signed by the Houses of Parliament in 2004 and it has never been put into practice. 

Well, we can hopefully help to provide parents with some information on the subject and the first question we received is: how do you advocate for your child to get the best help when you just know something is wrong, but you go to your GP and must return again and again for months on end until you finally get to the point where something is done? 

Unfortunately, sometimes it takes years. I remember one child who was referred to me and the letter from the GP simply said that the mother had pestered him so much that he had no choice but to refer. He said on this letter, black and white, that he didn’t think allergies existed. Interestingly, sometimes things that are completely not allergy-related, like stomach pains or runny noses, are referred as an allergy but when you look at the history there is nothing to do with allergies. It’s very sad because if we investigated children with simple things like hayfever, lots of them wouldn’t have developed asthma because you can prevent it. 

My three-year-old daughter has a peanut allergy and I had peanut butter every day in my pregnancy with her. Could there be a link and could she grow out if it?

There’s a bit of conflicting research on that one. Current research says mothers should include all sorts of allergens in their diet, unless of course they are allergic to them. There is a study that says because the protein is spread into the amniotic fluid and the child is ingesting them, in theory, you should be increasing the tolerance of the child because they keep on swallowing it. However, there is also a massive study currently being undertaken in Scotland that is looking into whether it can actually cause sensitisation.  So, what we say to mothers is do eat allergens because the evidence so far is that you will prevent it.

In this case with the mother who ate peanut butter throughout her pregnancy and the child is allergic, it’s going to be impossible for me to say a yes or a no. The likelihood is that the baby came into contact with the peanut protein after birth and the absorption through the skin may have lead to sensitisation and subsequently the allergy. I wouldn’t be surprised that what caused this child to become allergic to peanut was not what the mother’s ingested but the peanut that exists in the home environment. 

Do you find with things like that, not with severe allergies, but more mild ones, do you find that children grow out of these or can?

It’s impossible to predict. We would hope that children with mild allergies would outgrow them, but for me, it depends on a couple of important things – early diagnosis and early intervention. One of the things that I do is ‘Oral Immuno-Therapy', which is trying to introduce allergens as soon as possible. Even if they have tested positive, I try to do that and begin with small amounts and try to build it up. By doing that, you really increase the chances of a child growing out of an allergy. If you aren’t able to do that and you delay, the likelihood drops a lot.

My son has a big problem with all dairy and I always test the milk ladder and he sometimes gets to skimmed milk or a bit further and it always upsets his tummy in the end. Would you say keep trying and keep trying?

One of the things about the milk ladder is that there are two milk ladders. There is a six step one and a twelve step one. The six step one is the more recent one and the twelve step one is the older one. For me, and the outcomes I have seen, the twelve step one works better and is the one I’d advise. Some parents think that there are too many jumps on the six step one and one of the reasons why the twelve step one was removed is because they said on the higher steps there was too much sugar. Putting it into perspective, putting in the sugar on the one hand and outgrowing an allergy on the other, I'd say outgrow the allergy. Now, when a child starts reaching a stage where they are having a tummy upset like yours, I say, go back to the step in which there is no symptoms, stay there for a month or two and after a month or two, try it again. Because the milk ladder is trial and error, there’s no ‘one size fits all’.

Of course. And someone’s just said they are trying to get past the first step of the ladder. Do you just say, stop and start again a few months later?

Yes, give it a month maximum. Don't go much more than that.  

You can’t do damage with inflammation if they are getting upset tummies?

Well, that is the thing, if we’re talking about inflammation, something that is upsetting their tummies, if you get an inflammation anywhere on your body, your finger for example, and you don’t do anything, that will take 15 days to go away. Inside your body, because of ongoing processes, because the bowels do not stop, sometimes the inflammation can take a little bit longer. And that’s why we say with exclusions, a four to six-week period to deal with all that inflammation process. 

And last question on the milk ladder. Would you say go for the standard 12-day ladder or some people have one where they use ghee instead of butter, not more holistic, but perhaps not so shop-bought?

Put it this way, when people do the 12-step ladder, there are a lot of foods that go into each step. But if you put a lot of foods there, instead of helping parents, you can actually create even more confusion. So that’s why I advise sticking to only one or two foods. But if your child is being seen by a good paediatric dietician they can advise on changing certain elements. A good example of that for instance is that around the Midlands there is a large Asian community so there is a specific Asian milk ladder, as sometimes they can find ‘Western’ foods harder to incorporate into their diets so it can definitely be modified as required.

Is it OK to give my newborn baby probiotics? Why would a breastfed baby need this if they get everything from their milk?

Yes and no. This comes into a very interesting and complex area of allergy called biodepletion – basically, the lack of bacteria in the gut. Bacteria has decreased in children and although breastfeeding is amazing, you must also think of how many children are born via caesarean section and not by normal vaginal delivery. We know that being born by normal vaginal delivery will increase a baby’s gut bacteria and decrease their chances of developing allergies in the future. There was a study done in 2020 about a specific probiotic that, if given even to breastfed babies, you’ll decrease the incidence of Hayfever. It’s therefore not just about going to a supermarket and buying all or any of them, there are specific probiotics that can be used and that’s the thing about guiding people to the right probiotic.

My 20-week-old breastfed baby has multiple allergies and we can’t seem to get on top of them. I’ve been dairy and soya free for 14 weeks and gluten and egg free for 8 weeks and, as a result, there are all sorts of problems. Our GP has said that the baby has reflux, they are very unsettled, have very congested nappies, mucus and naps are terrible. We’re thinking of Neocate, so wondered how quickly should we see an improvement in symptoms and hopefully see the baby more settled?

It’s a hard one, as every baby is different so something I’ve done with a different baby, may not work in this instance. We need to evaluate cases independently and in a case like this, I would need a dietician working with me. Jumping straight into an immuno acid like Neocate, sometimes isn’t the best choice. Sometimes, we need to see what else is involved. I like to start from scratch, as jumping over the top can often complicate things. Using a specially formulated formula is probably best and there are a number of studies that have been done into something called HMO, which is the sugars found in breast milk – as some mothers produce more than others. It is felt that formulas that have HMOs tend to be more beneficial than the other formulas. You can also look at the baby’s poo – if it is liquid then lactose free formula is better, whereas if it is solid poo then the baby would benefit from lactose. I would advise seeing an allergist and dietician together so that a tailored plan for the baby can be developed.

My baby suffers from reflux and is now 4 months old. Should I wean him early and where do I start?

No. That is a very common misconception, as people often think that if the baby eats solid food then it will go away, but it doesn’t work like that. There are specific reasons for us to wean a child early and those are to do with a strong family history of allergy with all the siblings having significant allergies, as well as eczema and asthma. Those are the reasons for telling someone to wean at 3 or 4 months of age. But weaning a child onto solids will not solve reflux. What will solve reflux mainly is the child growing, muscles being steadier or sitting up and walking. It's a matter of gravity. So just giving solids won’t work.

My 3-year-old was diagnosed with eczema when he was one year old and it tends to be on his lower legs. It's manageable when we put on cream, but is there a reason he only has it here and will he grow out of it? I have asthma, do you think that could be linked?

We know that if there is a history of atopy in the family, there is increased risk of children developing atopy also and atopy related symptoms, eczema being one of them. Why is it on the lower limbs, not the upper limbs? Very often it’s to do with clothing and the rubbing of their clothing on the skin. If it is a mild eczema that is managed with moisturisers, I wouldn’t worry.  Very often, people who have eczema have it for the rest of their lives because eczema, you don’t outgrow it. You can either manage it, or not manage it. And most people who have it, can use moisturisers and manage it and live with it perfectly with moisturisers. Very interestingly, there is a study around limescale in water and how that can cause issues. I have some families from mainland Europe (which has much lower rates of limescale) who say, when I go with my child over there, their eczema disappears.

How do I know if my child has a milk allergy?

Firstly, they need to know the symptoms. And they need to know the symptoms of IG and non-IG. If the symptoms are immediate – hives, swelling, vomiting – within minutes, up to 2 hours after, then it is IG related and we can do a skin prick test which gives you a result in 15 minutes. If it is non-IG mediated, so we’re talking about many hours to one day later and is associated with diarrhoea, constipation, flare ups with eczema and reflux, there is no test for that and you then, with the help of a dietician, have to exclude certain things and then re-introduce them.

What is normal in terms of stools and skin when introducing new foods when you’re weaning?

Stool-wise, they might be changed. Stool might get looser because as you’re weaning, several things are going to happen. First, as you’re introducing new foods, you’re introducing new bacteria into the gut. So the first time you add a new food, the gut is not completely ready for it, so very often you’ll get a loose stool. That's fine and as long as the stool isn’t liquid then I wouldn’t worry. Skin, I wouldn’t expect any changes.  

What happens with children when they have tomato? Very often they’ll get a ring around their mouth?

That is not an allergy. You'll see it with tomatoes and strawberries – they are the most common – but also berries can cause it too. There are two main reasons for this. Firstly, most of these foods have histamine on them and that is what mediates an allergic reaction. Secondly, these foods are very acidic and it’s the acid on the baby’s soft skin that can cause it to go red. The skin is very sensitive, but I wouldn’t worry about that.

Is that why you have it with kiwi or pineapple, when your mouth goes a bit fuzzy?

That can be a pollen food syndrome or an oral allergy syndrome. So especially for people who have Hay fever, that can happen. It can be the acidity or it could be a latex allergy. Latex allergy is more commonly associated with bananas but it can be associated with kiwi. So, anyone who comes to me with odd sensations in their mouth with banana or kiwi, I test them for latex and tree pollen allergies, especially birch, as it could be a tree pollen allergy.

Which foods are likely to cause allergies when weaning? Obviously nuts and I've heard about strawberries and tomatoes?

OK, start by introducing egg as that can usually be the first thing that tends to cause allergic reactions that I see, as well as peanuts. Reactions to fruits and vegetables are rare. When you introduce fish or meat, fish can cause allergic reactions but it's rare that meat will cause a reaction. The other ones are wheat and oats as when you introduce bread or porridge, they could be allergic. It’s always good to keep a food diary, as if I see a child at one year and I ask the parents to think back to two or three months of age, very often parents don’t remember. It's very hard.

I know that vitamin D can help the immune system, but would it also help with things like eczema and asthma? 

There’s no evidence that it would, but I do tell everyone I meet to take vitamin D - because most people’s sun exposure is very low. The full role of vitamin D is yet to be understood but it is an amazing vitamin and it does boost the immune system. Certain people have been doing studies on the prevention of asthma and eczema and some studies say they have no effect, some are saying they have marginal effect. What I say is, you don’t stand to lose anything at all by taking it.

At what age does reflux warrant investigation? 

It is not age specific. If it is problematic, it needs investigation. You just need to find out what investigation you need to do. Like with anything in medicine, not just in allergy, start from scratch and keep it simple. People often try to complicate, but I say to my juniors, what is rare is rare, so let’s investigate that last. What is common is common. Address first the common issues and if they are not solved by that, start building up. If it comes to a point where nothing works with the child and the mother, then you need to start further investigations. It's not a matter of age, it’s a matter of what has been done before and what have you reached now. In paediatrics, there’s no one size fits all, like in adults.

One other thing about reflux, there are different types. Silent or not. With my children it was very clear to see. There was so much milk just coming out and spilling out of their mouth throughout the day, but lots of people have this silent reflux. How do you know if you’ve got that?

With silent reflux there are a few things we normally look for. If a child has just finished feeding and you lie them down and they refuse and you have to carry them for hours before they settle it can be a sign of silent reflux. The other one is hiccups, as frequent hiccups can be a sign of reflux.

Anything we’ve missed?

If any parents are worried they should go to their GP and ask for a referral to a dietician, allergist or paediatrician. Because if they are worried, things should be carried on. I would wish that as soon as any child has an allergic reaction that they come to me because it would make all our lives easier.

To speak to Dr Costa yourself about any of the issues discussed in this blog, you can contact him at or follow him on Instagram @childrensallergy