Asthma of the oesophagus: the alarming rise of a rare inflammatory condition

‘It can stretch more than three times its width to accommodate particularly large chunks of food’: an illustration showing the oesophagus on X-ray. Photograph: Libre de Droit/Getty Images

Lisa Thornton was heavily pregnant and in her early 30s when she noticed the feeling of a blockage in her oesophagus, the muscular food pipe that connects the mouth to the stomach. “At the time, I just thought it was just the pregnancy,” says Thornton, now 50, who lives in the New Forest in Hampshire. “I thought it was everything pushing up. But a few years later, things started to get worse.”

During a Sunday roast with her family, a chunk of broccoli suddenly lodged in her throat, causing spasms that persisted for hours. Any attempts to wash it down with water failed as the fluid simply came straight back up. Thornton drove to a nearby drop-in centre, where doctors tried, without success, to free the blockage with muscle relaxants.

After nearly 20 hours, she ended up in A&E. “I was put on a drip and the doctors started to talk about an operation to stretch my oesophagus to release the obstruction,” she remembers. “As a last-ditch attempt, a young doctor gave me morphine [which has a muscle relaxant effect as well as being a painkiller]. I woke up to find that, after 36 hours, the lump had finally cleared. It had been a violent, shocking experience and no one seemed to know why or how.”

But this was only the beginning. It would take another decade, and more incidents, before Thornton finally received a diagnosis: a little-known condition called eosinophilic oesophagitis (EoE), or asthma of the oesophagus.

Few of us think about how much we rely on our oesophagus on a daily basis. Normally less than a centimetre wide when relaxed, it can stretch more than three times its width to accommodate particularly large chunks of food.

“It’s common to swallow a piece of solids that is two to two and a half centimetres in size,” says consultant gastroenterologist Prof Stephen Attwood. “The oesophagus has to have that stretchiness to be able to open and allow food through.”

But for patients such as Thornton, the lining of the oesophagus becomes chronically inflamed, making it stiff, swollen and unable to stretch, as well as prone to food blockages. The condition is caused by an excessive immune reaction, driven by specialised white blood cells known as eosinophils. We require these cells to eliminate harmful intestinal bacteria and parasites, but when the immune system becomes miswired they can trigger allergic reactions and eczema.

When Attwood first identified EoE in the late 1980s, it was vanishingly rare, with estimated rates of less than 10 per 100,000 people. But just like food allergies, which are also mediated by eosinophils, EoE has become increasingly common in all age groups, from young children to the over-70s, for reasons we do not fully understand.

Estimates from the British Society of Gastroenterology suggest that it now affects approximately 63 in 100,000 people, which Attwood says is sufficient to make it technically “a common disease”.

One 2022 study in Sweden even suggested that it could affect more than one in 1,000 individuals – twice as many. “That’s the highest current estimate, but it fits entirely with what we see in daily practice,” says Attwood. “More and more patients are coming through needing assessments for this swallowing difficulty and we know we’re diagnosing it more frequently.”

So what is going on? Hannah Hunter, an allergy dietitian at Guy’s and St Thomas’ NHS foundation trust, has been seeing patients with EoE for the past decade and points to various theories – ones that have also been linked to the rise of allergy, asthma, eczema and hayfever cases. Among the most discussed is the hygiene hypothesis, which attributes the rise of EoE to modern cleanliness resulting in fewer childhood infections to train the immune system and therefore making it more susceptible to going awry.

Prolonged damage to the sensitive cells lining the oesophagus from modern diets and common chemicals such as pesticides and detergents have also been discussed as a plausible explanation.

Many patients with the condition are misdiagnosed with indigestion or gastroesophageal reflux disease

“Data does suggest there has been a genuine increase that is not explained purely by increased awareness,” says Hunter. “There are many theories as to why – less exposure to microorganisms at an early age, low vitamin D, and more exposure to highly processed foods that include additives, preservatives, sweeteners and emulsifiers.”

But while EoE is on the rise, awareness among many GPs is limited. Reports suggest that it takes an average of six years for patients to be correctly diagnosed. While an effective medicine known as budesonide, whose brand names include Jorveza, is now available, many patients are misdiagnosed with indigestion or gastroesophageal reflux disease.

If left for many years without the appropriate treatment, EoE can advance to the point where patients are left with thick scarring throughout their oesophagus, resulting in them being unable to eat normally or even swallow a small tablet.

Prof Kamila Hawthorne, chair of the Royal College of General Practitioners, says that detecting such a condition is not easy for doctors: “GPs have the broadest curriculum of any medical speciality, yet the shortest training programme, at just three years. Full diagnosis [of EoE] requires a thorough examination and a sampling of the oesophagus in secondary care settings.”

Diagnostics companies are now working on ways to make it easier for doctors to pick up EoE without requiring a full endoscopy, where a long thin tube containing a small camera is inserted down the patient’s throat. In December, the Cambridge-based gastrointestinal health company Cyted announced it had received a £1m grant from Innovate UK, Britain’s innovations agency, to expand the use of its EndoSign capsule sponge test (commonly used to diagnose and monitor Barrett’s oesophagus, a precursor to oesophageal cancer) for EoE.

“This would allow for patients to be tested more quickly and with less discomfort than an endoscopy but with the same accuracy,” says Marcel Gehrung, chief executive and co-founder of Cyted.

Hunter says we still need to understand more about the role of different foods in triggering the underlying inflammation that drives EoE, most commonly cow’s milk, wheat and eggs. While EoE is very different from the reactions commonly associated with food allergies, certain foods are known to potentially exacerbate the symptoms.

“It would be good to know more about the role of diet in inflammation beyond specific food triggers,” says the allergy dietician. “There is evidence that the way we eat can influence our immune system and so may have an effect on EoE. Highly processed foods, sugar and trans fat may have a detrimental effect.”

For Thornton, EoE meant that her whole life soon became centred on avoiding different foods and a worsening anxiety around eating, particularly in social situations. Having been misdiagnosed for so long, she was unaware that there was a new drug for the condition until a chance meeting with Attwood two months ago, mediated by a patient organisation.

Based on Attwood’s recommendations, she switched to a new consultant and recently started taking Jorveza, which has already had a marked improvement on her life.

“It should be diagnosed a lot quicker as it has such an impact on your life,” she says. “I’ve been taking Jorveza since just before Christmas and it’s made such a difference. I actually had a steak last week, which I never would have done before.”