Authors' response to detection of causative foods by skin prick and atopy patch tests in patients with eosinophilic esophagitis: things are not what they seem

Eosinophilic Esophagitis and Gastroenteritis

Eosinophilic gastrointestinal disease (EGID) can be classified as eosinophilic esophagitis (EoE) when the eosinophilia is limited to the esophagus or as eosinophilic gastritis (EG) if it is limited to the gastric tract, eosinophilic colitis (EC) if it is limited to the colon, and eosinophilic gastroenteritis (EGE) if the eosinophilia involves one or more parts of the gastrointestinal tract. EoE is by far the most common EGID. It is a well-defined chronic atopic disease due to a T helper type 2 (Th2) inflammation triggered often by food allergens. EoE diagnosis is done if an esophageal biopsy shows at least 15 eosinophils per high power field (eos/hpf). Globally accepted long-term therapies for EoE are the use of swallowed inhaled steroids or food antigen avoidance. The treatment of EoE is done not only to control symptoms but also to prevent complications such as esophageal stricture and food impaction. EGE cause non-specific gastrointestinal (GI) symptoms and are diagnosed if esophagogastroduodenoscopy (EGD)/colonoscopy show eosinophilia in one or more parts of the GI tract. They are rare diseases with an unclear pathogenesis, and they are poorly defined in terms of diagnostic criteria and treatment. Before initiating treatment of any EGE, it is imperative to conduct a differential diagnosis to exclude other causes of hypereosinophilia with GI localization. EGE are often poorly responsive to therapy and there is no commonly accepted long-term treatment. EG has many characteristics similar to EoE, including the fact that it is often due to a food allergen-driven Th2 inflammation; transcriptome analysis however shows that it is more a systemic disease and has a different gene signature than EoE. EC is a benign form of delayed food allergy in infant and is instead a difficult-to-treat severe inflammatory condition in older children and adults. EC in the latter groups can be a manifestation of drug allergy or autoimmune disease. Overall EGE, EC, and EG are rare and are a diagnosis of exclusion until more common causes of eosinophilia have been excluded.

Role of mucosal inflammation in eosinophilic esophagitis: review of the literature

Eosinophilic esophagitis (EE) is increasingly recognized in adults. It is an inflammatory disease of the esophageal mucosa, with variable presentation, unresponsive to acid suppression therapy. The diagnosis requires histological confirmation of intense eosinophilic infiltration on esophageal biopsy specimen, however exact criteria required to make a diagnosis of EE is still being debated and a clear differentiation from gastroesophageal reflux disease (GERD) is important. Allergen elimination or anti-inflammatory therapy may be effective in such patients. The imperfect diagnostic criteria for EE mandate an understanding of the immunology and the pathophysiology of the disease. It may facilitate the introduction of novel treatment modalities in an individual unresponsive to acid suppression therapy. This paper describes basic elements of the immune-mediated injury to the esophageal mucosa and management aspects to provide a better understanding of the condition.

Eosinophils and allergic diseases of the gastrointestinal tract

The association between increased tissue eosinophilia and allergic disease is particularly striking in the case of the gastrointestinal tract. About 80% of individuals with eosinophilic gastrointestinal disorders (EGIDs) are atopic, while half of the patients with gastrointestinal allergy show tissue eosinophilia. The function of eosinophils in gastrointestinal allergic disorders is unclear; however, a proinflammatory action is most likely. Cytokines (interleukins 5 and 3, granulocyte-monocyte colony-stimulating factor) and chemokines (eotaxin, RANTES, etc.) released by Th2 lymphocytes, mast cells and other tissue cells have been identified as major regulators of eosinophil chemotaxis and activation, but a convincing mechanism by which eosinophils are activated in an allergen-dependent manner is still lacking. The diagnostic approach comprises both histological and laboratory methods to assess eosinophilia and eosinophil activation, as well as tools to assess the allergic disease while excluding other gastrointestinal diseases such as food intolerances, infections and tumours. Treatment of allergic EGIDs includes elimination or elemental diets and drug therapy using classical anti-allergic agents such as topical corticosteroids and new approaches such as LTD4 receptor antagonists or antibodies against IL-5 or eotaxin.

Atopic characteristics of adult patients with eosinophilic esophagitis

BACKGROUND & AIMS

The association of sensitization to food allergens, atopic disorders, and eosinophilic esophagitis (EE) is well known in children, but not in adults. Our purpose was to identify the spectrum of specific allergic sensitivities to environmental and food allergens within a series of adult patients with EE.

METHODS

The case series consisted of 23 adult patients with biopsy-proven EE referred for allergy evaluation at an academic clinic. All patients had data that included serum measurement of specific immunoglobulin (Ig)E antibodies to common foods and spices. Patients diagnosed with allergic rhinitis had a relevant clinical history of respiratory allergy and evidence of specific IgE to environmental aeroallergens.

RESULTS

The series consisted of 16 men and 7 women with a median age of 34 years (range, 18-57 y). Eighteen of 23 had an atopic diathesis, allergic rhinitis being the most common. Seventeen of 21 patients were polysensitized to several different environmental allergens, and 19 of 23 (82%) had serum IgE specific for one or more food-associated allergens (median, 5 foods), with wheat, tomato, carrot, and onion identified most commonly. The preponderance of environmental and food allergy was similar across all age groups and did not favor younger adults.

CONCLUSIONS

By using objective measures, our series confirms the high degree of atopy in adults with EE, similar to that seen in the pediatric population. These patients tend to be polysensitized to several environmental allergens, and the profiles of serum IgE specific for food allergens suggest that sensitization may partly be a response to inhaled allergens.

Eosinophilic esophagitis: association with allergic disorders

Atopy has been linked to eosinophilic gastrointestinal disorders because of the role eosinophils play in atopic disorders. It has also been found that these disorders coexist. The goal of this article is to take a step back, and considering only eosinophilic esophagitis, attempt to determine from the available body of clinical and research literature: (1) Is the coexistence of these disorders attributable to a preconceived bias? If so, what is the source of the bias and how can it be removed? (2) Is there a cause and effect relationship? If so, can this relationship be harnessed for diagnostic and therapeutic modalities?

Eosinophilic esophagitis: is it all allergies?

Eosinophilic esophagitis (EE) is an increasingly recognized disorder in the adult population, most often manifested by symptoms of dysphagia and food impaction. Mechanisms involving eotaxin-3, interleukin 5, and signal transducer and activator of transcription 6 have been studied and may represent future therapeutic targets. Patients commonly have a personal and family history of atopy, and both food allergies and aeroallergens have also been investigated as triggers of EE. Traditional allergy-testing methods, including skin prick testing and specific IgE testing, have been used to identify food and environmental allergies. However, new studies suggest that patch testing could add to diagnostic accuracy in EE because the disorder might not be a classic type I allergic response. Although studies of treatment of adults with EE have thus far focused on swallowed fluticasone proprionate, many trials in children have assessed the efficacy of food elimination and elemental diets. These diets, which have been extremely successful in reducing symptoms, have also been shown to induce histological improvement and remission. No similar studies have been conducted in adults; the tolerability of such an intervention may prove more difficult in this population. This article reviews the underlying pathophysiology of EE and describes evolving options for more accurately identifying food and environmental allergies. We also discuss the pediatric trials using food elimination and avoidance diets and suggest that this type of intervention may be an important area of future research in the adult population.