Indroduction

Eosinophilic gastroenteritis (EG) is a rare chronic inflammatory condition in which a type of white blood cell, called an eosinophil, overgrows within your digestive tract. It causes an allergic-like inflammation reaction, primarily in your stomach and small intestine. Eosinophils are part of the immune system that fight foreign objects; however, in EG, they get a false alarm and attack your digestive system incorrectly, causing inflammation and damage. The exact way this happens remains unknown, but hypersensitivity likely plays a major role, with lots of patients having a history of allergies.^1,2

Here, we will delve deeper into EG and the way your immune system malfunctions. You will be able to identify the symptoms, so you can recognise the condition. If you do have EG, you can still live a healthy and active life through symptom management.

Eosinophils and their link to allergies

White blood cells are a major component of your immune system and provide an element of protection against invading organisms by preventing them from growing and subsequently causing damage. The three main types of white blood cells are: granulocytes, lymphocytes and monocytes, with eosinophils being a type of granulocyte. When your body detects an invader and there is inflammation, eosinophils will target the area, releasing a bag-like structure that contains enzymes for fighting the infection. They comprise approximately 1% of cells within your body and take on a spherical shape when they are made within bone marrow.

https://app.biorender.com/illustrations/68d690d6488a7d0ed970d4db?slideId=59ce1a1d-5495-4dd7-85ca-84cd3d6cfbd7

There is a correlation between EG and those with food allergies, asthma, hay fever and eczema. People with EG tend to have either a personal or family history of a genetic tendency to develop allergies. Eosinophils react to deal with the food a person has ingested that they are allergic to. In those with EG, eosinophils accumulate within the gastrointestinal tract, the pathway through which food moves during digestion, in the stomach and small intestine, causing inflammation and damage.^3,4,5

The root of the problem

EG is characterised by a person’s immune system going wrong. A trigger, most commonly a food high in protein, is falsely identified as a threat to your body. The trigger releases a signal for eosinophils to gather in your stomach and small intestine. Eosinophils then release a toxic protein, which targets and destroys invading organisms, but in this case, attacks your own body. The attack can result in chronic inflammation and damage to the stomach and small intestine, which can impair their normal function.^3,6

The mechanism causing the immune system to attack your body remains unknown, but potential triggers are known. EG can be triggered by food allergies, with the main allergens playing a major role. These include:

• Gluten
• Eggs
• Milk
• Nuts
• Soya
• Celery
• Crustaceans
• Fish
• Lupin
• Molluscs
• Mustard
• Peanuts
• Sesame seeds

Despite being a rare disease, EG can affect anyone. However, genetics potentially play a role in the onset of the condition, meaning it may run in families. Other conditions, such as atopy, which include asthma, hay fever and eczema, may contribute to the onset of the EG.⁴

Who is affected by eosinophilic gastroenteritis?

EG is currently classified as a rare disease and only affects around 0.01% of the population. Despite affecting both men and women, EG has been seen to be more common in the male population. The condition is most likely to arise between the ages of 20 and 50 years, but has been seen in children.⁴

Symptoms

With eosinophilic conditions, symptoms vary depending on the part of the digestive system that is targeted by eosinophils and the layer of the gastrointestinal wall that has been infiltrated. Common symptoms include:⁴

• Nausea
• Vomiting
• Abdominal pain
• Bloating
• Heart burn
• Feeling full after only a few bites
• Weight loss
• Fatigue
• Diarrhea
• Difficulty swallowing

Diagnosis

To diagnose EG effectively, a combination of steps is required. These steps will include a physical exam, medical history and blood tests to rule out other conditions. They also include other tests that can further confirm the diagnosis of EG.^6,7

Endoscopy

An endoscopy is used to confirm suspicions of EG diagnosis. An endoscopy involves a small camera inserted into your digestive system. The purpose is to observe for signs of swelling, irritation and injury to your stomach and small intestine. The presence of these signs can confirm a diagnosis.

Imaging studies

Ultrasound is capable of identifying ascites and thickening of the intestinal wall. A computed tomography (CT) scan can identify diffuse thickening of the mucosal folds, thickening of the intestinal wall, the presence of ascites, and any other obstructions. Imaging techniques can also help in biopsy guidance.

Biopsy

A biopsy is used in conjunction with an endoscopy to confirm EG diagnosis. A biopsy involves the removal of a small amount of tissue from potentially affected areas so it can be analysed for its eosinophil count. An increase in levels when compared to normal could be indicative of EG.

Allergy testing

Allergy testing cannot diagnose EG, but it can identify the cause. The purpose is to identify what caused the elevated eosinophil levels in your stomach. With allergens successfully identified, symptoms can be effectively managed.

Management and treatment

There is currently no cure for EG, but a person can live a healthy life with the correct management of their symptoms. The goal of treatment is to return the elevated eosinophil levels to normal and to prevent their re-elevation. An early diagnosis can be effective in preventing any of the more serious complications, something that is particularly important in infants, as they are more susceptible to the effects of malnutrition. 

Approximately 30 - 40% of patients can experience spontaneous remission, where their body naturally heals itself; however, the majority of patients will require ongoing treatment. Symptom management will ensure the comfort of a patient by alleviating symptoms. This could include medications, lifestyle changes and even surgery. For example:^4,6

Elimination diet

The purpose of an elimination diet is to remove foods that cause elevated eosinophil levels from the diet entirely. If a patient refrains from eating foods containing their allergens, their body should not signal an immune response.

Elemental diet

An elemental diet allows nutrition to be obtained from foods to which a person is allergic. The nutrients that would otherwise be obtained from allergen-containing foods will be replaced with a liquid formula.

Corticosteroids

Corticosteroids can help reduce swelling caused by EG. Examples shown to be effective are prednisone and budesonide.

Immunosuppressants

Immunosuppressants, such as azathioprine, are medications that can be taken to decrease the effects of your immune system, including swelling and eosinophil levels.

Surgery

In severe cases, when your intestines are blocked, surgery can be used to physically unblock them.

Living with eosinophilic gastroenteritis

Individuals with EG can live a comfortable and active lifestyle if they receive an early diagnosis and an effective treatment plan. It is important to be able to recognise symptoms and seek medical attention if you suspect you may suffer from EG. A diverse team, including dieticians and gastroenterologists, can achieve a diagnosis, identify the root cause and devise a treatment plan for you.

Summary

Eosinophilic gastroenteritis (EG) is a rare chronic condition where eosinophils, a type of white blood cell, incorrectly attack the digestive tract, causing inflammation primarily in the stomach and small intestine. This condition often relates to a history of allergies, leading to a misinterpretation of food or other items as threats. While the cause of this immune response is unknown, triggers typically include certain high-protein foods like gluten, eggs, and nuts. EG can affect anyone, particularly men aged 20 to 50, and has symptoms such as nausea, vomiting, abdominal pain, and difficulty swallowing. Diagnosis involves physical exams, blood tests, endoscopies, and biopsies to confirm elevated eosinophil levels.

There is currently no cure for EG, but treatment focuses on managing symptoms and normalising eosinophil levels. Options include elimination diets to avoid allergens, elemental diets providing nutrients through liquid formulas, and medications like corticosteroids to reduce inflammation. Some patients may experience spontaneous remission, but ongoing treatment is often necessary. Living well with EG requires early diagnosis and a tailored treatment approach, ideally involving a team of healthcare professionals to manage symptoms effectively and ensure a comfortable lifestyle. Recognising the symptoms and seeking medical support are essential steps for those who suspect they have this condition.