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From developing a mild rash after drinking milk, to requiring an auto-injector in case of anaphylactic shock, having a food allergy can be at best, inconvenient, and at worst, life-threatening. But are there food allergies which we can grow out of? We asked the experts.

The difference between a food allergy and intolerance

A sees your body produce a chemical imbalance to certain foods, which can lead to feeling bloated, having an upset stomach, developing a rash or feeling itchy. “The reactions tend not to be life-threatening, they can be debilitating though,” says Professor Clare Mills from Manchester University. Examples include being lactose or gluten intolerant.

A food allergy is when your body’s immune system creates a response to proteins in foods which it deems unsafe. Medically, they are referred to as an . “IgE is an antibody that normally we produce, to fight parasitic infections like malaria. And for some reasons, people can develop them to things like pollen and get hay fever and also foods,” explains the allergy expert who, in addition to her role as Professor of Molecular Allergology, is currently carrying out research to discover just how common .

The reason why food allergies are regarded as so dangerous is that while for many the allergic response is relatively mild, for others it can quickly deteriorate and become life-threatening. What’s more, for some, only a tiny amount is required to have a reaction – hence why on packaging you may see warnings such as ‘may contain traces of nuts’.

Prof. Alexandra Santos is a Professor in Paediatric Allergy at King’s University and works as a paediatric allergy consultant at Evelina London Children’s Hospital. She explains that in babies and children; “the most common food allergies universally are cow's milk and egg allergies and, in the UK, also peanut, tree nuts and sesame seed allergies.”

Signs of a food allergy are wheezing, swelling - especially on the face or in the mouth or throat, difficulty swallowing and tingling in the mouth. However, other symptoms can be easily confused with those of an intolerance – such as rashes and itchy skin, diarrhoea and sickness. This is why it’s important to have the allergy diagnosed by a professional – to clarify exactly what the problem is. “It is indeed more common for people to report a food allergy, than for people to have a food allergy confirmed after a proper diagnostic assessment,” says Prof. Santos.

She continues: “The diagnosis of food allergy requires testing for increased IgE antibodies specific for that food. However if this comes back as inconclusive, then the next step would be an ‘oral food challenge’. This involves the patient eating the food to see if there is a reaction. This is done under strict medical supervision, with the patient closely monitored so that if there are any allergic symptoms they can be immediately treated.”

Amena Warner is head of clinical services at the charity, Allergy UK and says that even if symptoms are small, you shouldn’t downplay it and should seek medical help to clarify whether it is indeed an allergy. “And the more serious the reaction, the more important it is to get some clarity on what it is causing the allergic reaction and how you can manage that.”

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Who’s at risk of developing allergies?

“We know children with severe eczema are more risk of developing food allergies. We think that's through the broken skin barrier… allergens can get into the skin to sensitise the infant usually before they develop oral tolerance,” says Amena who has 20 years of experience as a clinical nurse working with allergies.

“Don't be surprised or scared if the GP looks at the eczema and thinks it might need some steroids to get it under control. Because the longer you leave eczema, that is weepy or cracked and red and inflamed that skin, the higher the probability is that it could lead to developing food allergies.

“There is also evidence that there are risk factors from those who are already allergic to or to be more at risk of developing things like peanut allergy,” Amena adds.

Can you prevent allergies to begin with?

When pregnant should you circumvent certain foods that are known to cause allergies? Only if you are yourself.

Likewise, when weaning you shouldn’t avoid common food allergens, unless there’s a , in which case you should seek advice from a healthcare professional.

For those without a history of food allergies, “there is a lot of evidence now that early instruction of food into the weaning diet helps,” says Amena before adding: “Your baby’s less likely to develop an allergy if given these foods when weaning between 6-12 months, than if you avoid all the allergens, because the body needs that immunological recognition of those food allergens.”

The good news is, lots of people grow out of their food allergies, but it really does depend on what you’re allergic to. Prof. Santos says: “Cow's milk, egg, wheat and soya allergies are frequently outgrown whereas peanut, tree nut, sesame, fish and shellfish allergies tend to be more persistent with a large proportion being lifelong.”

Prof. Mills adds: “IgE mediated allergies to milk and egg are common in infants and young children. But blessedly, they grow out of it. So, it's almost like a different sort of allergy which they get when they're very young and as their immune system and their bodies mature, they grow out of.

“To be IgE mediated allergy to cow's milk (as an adult) is very unusual. We ran a birth cohort study across Europe with many thousands of children enrolled and when we did the school age follow-up there wasn't a single cow's milk allergic child left. But we had about one and a half percent when they were babies.”

You know that saying, ‘don’t try this at home?’ that rings true with testing to see if you’re growing out of an allergy. Don’t be tempted to just ‘try a little bit’ to see how your body responds.

“You should never experiment with any of this at home. It's just not safe,” warns Prof. Mills, before adding: “One of the things that we know with food allergy, is that many people who have a severe reaction as adults, may not have had any history or had any warning sign or a bad reaction before, so if you think you've got a food allergy, I would not try the food at home - you really need to get properly assessed by an allergist.”

Prof. Santos agrees, highlighting how important controlled conditions and medical supervision are in determining if you no longer have an allergy to food: “In clinic, we monitor the development of tolerance with the support of the same allergy tests that we use to confirm the diagnosis of food allergy. A decrease in the IgE levels specific for that food is often an indication that the allergy may be resolving.

“The dose at which an allergic patient reacts to varies from patient to patient and with the food in question. When we do a food challenge, we start with very small amounts of the allergen and gradually increase, monitoring very closely and stopping at the first signs of an allergic reaction to treat any symptoms. This way, each patient will eat the minimum amount needed to trigger a reaction, if any. Food challenges are currently the best test to confirm a food allergy.”

In future there might be treatments for ALL allergies

Even if your allergy is likely to be lifelong, help is at hand and all the experts are excited about what’s currently available and what could help in future.

“There is a treatment that has been approved for peanut allergy called . It is not a cure but can reduce sensitivity so people have a much reduced risk of accidental reactions,” says Prof. Mills before adding: “And, there are therapies being developed for other foods like milk, and egg and tree nuts.”

Prof. Santos finishes: “There are many studies underway and others in development to assess the effect of various interventions in the development of food allergy. I am hopeful that we will be able to intervene and modify the course of the disease and prevent new cases in the future.”