Finding a safer way to spot dangerous allergies


Alexandra Santos is a senior clinical lecturer who specialises in children’s food allergies at King’s College London and Evelina London Children’s Hospital.

Food allergies are on the increase. In the UK, between five and eight per cent of children are affected. Having an allergy has a profound effect on everyday life and, as recent events have reminded us, allergic reactions can be fatal.

At the moment, the gold standard for allergy testing is the ‘food challenge’ where patients are exposed to allergens in a controlled medical environment to ascertain their allergic reaction.   

However, a food challenge can be an unpleasant experience resulting in sickness and stomach pains, rashes and swelling, coughing and breathing difficulties. They can also be dangerous. The severity of a reaction is unpredictable and patients could potentially go into life threatening anaphylaxis.

Still, these food challenges are needed. The current alternatives – skin prick and blood tests that measure antibodies to specific allergens – are inaccurate and they often suggest someone has an allergy when they do not.

I am working on a couple of new tests where we expose the cells from a blood sample to allergens in a test tube. This is a much more accurate method and only if there is a negative result would patients be referred for the food challenge. This would make the process safer and ultimately more cost effective. 

In the Evelina London Children’s Hospital, we have successfully used the technique to test for peanut allergy.  We have developed the same technique to test for allergies to milk, eggs, cashew nuts and sesame seeds.

In the lab, we’re also investigating the way the immune system responds to food allergens. If we can understand at a molecular level why some people do suffer symptoms while others don’t, we may be able to find new treatments for food allergy.

The Academy of Medical Sciences supported me at a critical stage in my research career. I had just started my role as Senior Clinical Lecturer at the same time as I returned to work after maternity leave. I won a place on the SUSTAIN programme, which is designed to help more women researchers into leadership roles. The career development workshops, peer support and mentoring were key for helping me achieve independence and to feel confident and accomplished in my role.

I’m driven by the many unanswered questions we have in the field of food allergy and I am reminded of that day-to-day when seeing children in the clinic. We need to understand better why food allergies are becoming more common, to be able to reliably test for allergies without having to expose the patient to the allergen and to find definitive treatments and preventative strategies to halt the allergy epidemic.

I am passionate about food allergy and about medical science. It is an absolute privilege for me to do a job where I follow my curiosity, leading others along the way, and ultimately improving patients’ lives through my research.

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