From the Guidelines
Approximately 40% of anaphylaxis cases present with gastrointestinal (GI) symptoms, as reported in the 2010 guidelines for the diagnosis and management of food allergy in the United States 1. The underlying mechanism involves mast cell and basophil activation, leading to the release of inflammatory mediators like histamine and leukotrienes throughout the body, including the GI tract. GI symptoms in anaphylaxis can include:
- Abdominal pain
- Nausea
- Emesis
- Diarrhea These occur due to smooth muscle contraction, increased vascular permeability, and mucosal edema in the GI tract caused by the released mediators. It's crucial to recognize that GI symptoms may be the initial or predominant manifestation of anaphylaxis in some cases, as noted in the guidelines 1. This is particularly important in food-induced anaphylaxis, where GI symptoms can precede other systemic symptoms. Healthcare providers should be aware that the absence of skin or respiratory symptoms does not rule out anaphylaxis, and prompt recognition and treatment with epinephrine is essential, even if only GI symptoms are present in a suspected anaphylactic reaction. Understanding the prevalence and mechanism of GI symptoms in anaphylaxis helps in accurate diagnosis and timely intervention, potentially preventing progression to more severe manifestations of the condition, as emphasized in the guidelines 1.
From the Research
Presentation of Anaphylaxis with Gastrointestinal (GI) Symptoms
- The percentage of time anaphylaxis presents with gastrointestinal (GI) symptoms is not explicitly stated in the provided studies.
- However, according to 2, GI symptoms are more common with food allergies, and plasma histamine levels correlate with hives and GI symptoms.
Underlying Mechanism
- Anaphylaxis is a systemic, life-threatening disorder triggered by mediators released by mast cells and basophils activated via allergic (IgE-mediated) or nonallergic (non-IgE-mediated) mechanisms 3, 4.
- The reaction involves the release of histamine and other mediators, which can cause symptoms in various systems, including the gastrointestinal tract 2, 5, 6.
- The severity of anaphylactic reactions is variable, and some can be fatal 3, 5, 6.
Diagnosis and Treatment
- Diagnosis of anaphylaxis is based on the occurrence of characteristic symptoms, especially when they develop upon exposure to a potential trigger 5.
- Demonstration of an increase of mast cell tryptase serum concentration above the individual baseline value can support the diagnosis 5.
- Prompt treatment of anaphylaxis is critical, with subcutaneous or intramuscular epinephrine and intravenous fluids remaining the mainstay of management 3, 4, 6.