Coeliac disease is a common gastrointestinal condition (affecting approximately  one in every 100 individuals in the UK, of both sexes, presenting at any age) caused by an immune response to gluten, a type of protein found in wheat (bread, biscuits, cake, sauces, pasta etc), barley (beer, flavour enhancer) and rye (rye bread).  Importantly it is not a food ‘allergy’ - the immune response in the gut in coeliac disease causes damage to the intestinal lining which affects the absorption of important nutrients such as iron, folic acid, and vitamin D amongst others. Symptoms occurring after ingestion of gluten in coeliac disease are therefore of slower onset and recovery, and the condition is not usually associated with rapid development of symptoms after eating gluten.  Food allergies differ in that histamine is released after ingestion of the offending allergen and causes swelling in the airways and throat and an itchy skin rash (hives) - the symptoms characteristically come and go quickly and leave no residual tissue damage. Patients with food allergies therefore usually have a very good idea of the responsible culprit.    

Those with ‘classical’ symptoms of coeliac disease (diarrhoea and weight loss) only make up around 10% of all cases. The majority of symptoms associated with coeliac disease are more wide-ranging and may lead to misdiagnosis - bloating and altered bowel habit (including constipation) may be misdiagnosed as an ‘irritable bowel’, headaches as chronic migraine, and fatigue and ‘brain fog’ may be attributed to lifestyle factors. In view of the insidious nature of some of these symptoms and the lack of temporal association with eating gluten, it is thought that the average delay from the time of onset of symptoms of coeliac disease to diagnosis maybe as great as 13 years, and as many as 50% of cases are never identified throughout their lifetime.   

Coeliac disease is diagnosed by a blood test (for the IgA anti-TTG antibody) and confirmed by biopsy of the intestinal lining taken at endoscopic examination of the upper gastrointestinal tract (‘gastroscopy’). Biopsy can be omitted where the antibody test is very high.  It is treated by following a lifelong, absolute gluten free diet, which is challenging (given how commonly processed foods contain gluten) and requires considerable professional support from clinicians and dietitians. However once gluten is effectively eliminated from the diet the intestine recovers over a period of months and there should be no further health consequences of coeliac disease itself (although it can be associated with other autoimmune conditions).  

Other medical conditions can be associated with wheat or specifically gluten ingestion. True wheat food allergy occurs, as does a rare and unusual condition causing anaphylaxis when exercising after eating gluten.  Many people without coeliac disease report symptoms after eating gluten that could be gastrointestinal or systemic (fatigue, brain fog), and this condition is called ‘non coeliac wheat (or gluten) sensitivity’. The underlying cause of this condition has not been elucidated and there are no tests available for it.  It should be noted that wheat is also a prime culprit for causing symptoms of irritable bowel syndrome (IBS). 

Medicolegal Implications:  

Coeliac disease becomes of relevance to lawyers in a number of different scenarios. 

1. Clinical negligence

Coeliac disease rarely presents with life-threatening or acute symptoms. Diagnosis is frequently delayed as a result of chronic symptoms being attributed to other causes (as noted above) and although the blood test is cheap and simple to request it is often omitted from the diagnostic work-up.  The blood test does not perform well as a ‘screening’ test and is not used as such, only where there is a reasonable pre-test probability of the condition being present. It is therefore unreasonable to expect that the test is carried out initially on all individuals presenting to their GP. However, given that the symptoms associated with coeliac disease are diverse (and not limited to the gastrointestinal tract) and may not be recognised by the patient (who may consider fatigue, for instance to relate to lifestyle factors) coeliac disease can be easily overlooked. It then becomes a matter of dispute as to when the diagnosis might reasonably have been considered and when the blood test should have been taken when the diagnosis has been delayed. 

The two most significant long term complications of failing to treat coeliac disease are osteoporosis (leading to irreversible skeletal deformity such as kyphosis from vertebral body collapse) and a rare form of intestinal lymphoma (enteropathy-associated T cell lymphoma) which predominantly occurs in the setting of undiagnosed coeliac disease. This tumour carries a very poor prognosis and given that approximately 50% of those diagnosed are found to have coeliac disease that has gone unrecognised, there is potential for significant damages if missed opportunities for doing so are identified.   

Astonishingly, in a number of cases of delayed diagnoses, a prior positive blood test comes to light in the GP records from many years before that was overlooked and not acted upon.  In such situations, whilst patients may not have experienced significant complications of osteoporosis or have developed lymphoma, there may still be good grounds for claiming for long term symptoms (fatigue, ‘brain fog’, migraine) and their effects for instance on career progression and employment prospects. Whether untreated coeliac disease has any detrimental effect on female fertility remains contentious. 

Conversely, given that coeliac disease is so often undiagnosed, it is possible for a serious condition to be overlooked by the identification of coeliac disease as a potential cause. For instance, an individual may present with iron deficiency and be found to have coeliac disease on testing (which would be a reasonable cause). However, it may be that the coeliac disease had long been present in the background and the iron deficiency only recently developed as a result of the colonic carcinoma that then goes undiagnosed and should have been considered as a cause of iron deficiency. Such an oversight would constitute reasonable grounds for litigation.

2. Personal injury  

The classical scenario is that an individual with coeliac disease attends a function (such as a friend’s wedding) and requests gluten free food. They reiterate their requirements to the waiting staff and are given a bread roll which they are reassured is gluten free. A member of staff dashes out of the kitchen shortly after they finished eating the roll to tell them that this was given to the wrong person and the roll was in fact gluten-containing.   

Coeliac disease is not an allergy and therefore instant symptoms would not be expected. In this setting however, symptoms usually arise within 1-2 hours and include severe nausea and profuse vomiting lasting for one to two hours. The reason for this has nothing to do with allergic type (histamine) responses, but another chemical - interleukin 2 - released by primed immune cells in patients with coeliac disease who have been following a strict gluten free diet. The effect is usually short lived but can lead to a mild gastrointestinal upset over the following days. Longer term effects would not be easily attributable to one-off gluten exposure of this nature. 

In one well publicised case from 2023, an 80-year old patient with coeliac disease was inadvertently given Weetabix for breakfast in hospital and was found at inquest to have died following inhalation of vomit as a result.  

Patients with coeliac disease often report that they have been ‘glutened’ on the basis of experiencing non-specific gastrointestinal symptoms after eating out in a restaurant that they are not familiar with despite taking appropriate precautions to exclude possible gluten ingestion. Whether or not such cases are indeed due to inadvertent gluten ingestion is difficult to ascertain and ‘hypervigilance’ towards symptoms may play a part if an individual already has concerns about the safety of food preparation in the establishment.   

Given that those with coeliac disease represent only a small proportion of those who consider themselves to be gluten ‘intolerant’ or even ‘allergic’ a wide variety of different symptoms are reported following accidental or negligent gluten exposure. In such cases the evidence for the underlying condition needs to be considered and the possible plausible mechanism of the origin of symptoms, the timing of onset and their duration considered relative to the gluten ingestion. Recent placebo-controlled trials demonstrate that many people who consider themselves intolerant to gluten do not experience symptoms when they ingest gluten if they are not aware of having done so (and are therefore not strictly ‘gluten intolerant’!). However, symptoms may be precipitated as a result of anticipatory cues (for instance it may enough for a patient to consider that they have a reaction to gluten to develop symptoms after being told that they have inadvertently consumed it). ‘Hypervigilance’ may also play a significant part in the recognition of or severity of symptoms in this setting. Therefore, even when a patient does not have coeliac disease or wheat allergy or even a proven wheat/gluten intolerance, but experiences symptoms after the ingestion of gluten (having informed catering staff of an intolerance), it can be difficult to challenge causation regardless of the symptoms, their timing of onset and duration.   

3. Employment tribunals 

Whether or not coeliac disease represents a disability under the terms of the Equality Act 2010 may be disputed. Whilst those who are able to easily consume a gluten free diet will not experience any disability (except for the additional time, cost and effort required in pursuing the diet and checking food labelling) coeliac disease could be considered a disability if there is are impediments to following a gluten free diet at the workplace and there are indeed cases where discrimination has been ruled on such grounds. Furthermore, individuals with coeliac disease are currently barred from joining the UK armed forces as gluten free food cannot be guaranteed on active service, and similarly in other occupations where frequent travel may be required to destinations that cannot provide suitable catering.   

Summary  

Coeliac disease and other gluten-related disorders present significant litigation risk with certain law firms now specifically advertising the potential for successful claims following inadvertent gluten ingestion. In some cases, despite the lack of a recognised diagnosis of an underlying disease or a plausible biological explanation for the origin of symptoms, such claims may still succeed. Until there is greater clarity on the causation of symptoms after gluten ingestion, it is likely that the number of such cases will increase.