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Exercise-induced anaphylaxis

Exercise-induced anaphylaxis (EIA) is a rare, potentially life-threatening hypersensitivity reaction characterized by the sudden onset of allergic symptoms during or immediately following moderate to vigorous physical exercise, involving the activation of mast cells and the release of mediators such as histamine, which affect multiple organ systems including the skin, respiratory tract, gastrointestinal system, and cardiovascular system.^[1] This condition can manifest independently or in conjunction with specific triggers like certain foods, distinguishing it from more common exercise-related issues such as cholinergic urticaria.^[2] Symptoms of EIA typically begin within 30 minutes of starting exercise in the majority of cases and may include pruritus (itching) in up to 92% of patients, urticaria (hives) in 83-86%, angioedema (swelling) in 72-78%, shortness of breath in 51-59%, and loss of consciousness in about 32%, potentially progressing to severe hypotension, respiratory distress, or gastrointestinal upset if untreated.^[1] The reaction is often reported as more prevalent in women, though ratios vary from 1:1 to 2:1 across studies, and typically first occurs in young adulthood, during the second or third decade of life, affecting approximately 2-5% of all anaphylaxis cases, though exact prevalence remains low at around 0.017-0.031% in certain populations like Japanese students.^[1]^[3]^[4] Environmental factors such as warm weather or high humidity may exacerbate episodes. The pathophysiology is not fully understood but may involve immunoglobulin E (IgE)-mediated mechanisms in subtypes such as food-dependent exercise-induced anaphylaxis (FDEIA).^[1] A subtype known as food-dependent exercise-induced anaphylaxis (FDEIA) requires both exercise and prior ingestion of culprit foods—commonly wheat, shellfish, or nuts—typically within 4-6 hours before activity, highlighting the role of cofactors like nonsteroidal anti-inflammatory drugs (NSAIDs) or alcohol in lowering the threshold for reaction.^[1] Diagnosis relies on a detailed clinical history, exclusion of mimics, and confirmatory tests such as exercise challenge protocols under medical supervision, serum tryptase levels during episodes, or skin prick testing for allergens in FDEIA cases, emphasizing the need for specialist evaluation by an allergist.^[5] Acute management centers on immediate administration of intramuscular epinephrine via auto-injector, followed by antihistamines, corticosteroids, and supportive care in an emergency setting, while long-term prevention involves trigger avoidance, such as exercising with a partner, carrying epinephrine at all times, and prophylactic use of H1-antihistamines like cetirizine before activity; emerging options like omalizumab may be considered for refractory cases.^[1]^[3] Although no cure exists, these strategies allow most individuals to maintain an active lifestyle with careful planning.^[5]

Introduction

Definition

Exercise-induced anaphylaxis (EIA) is a rare, potentially life-threatening hypersensitivity reaction that occurs during or after physical exercise, characterized by systemic mast cell degranulation and the release of mediators such as histamine, leading to widespread anaphylactic symptoms.^[1] This condition represents a distinct form of physical allergy where exercise acts as the primary trigger, potentially exacerbated by cofactors like certain foods or medications, though it can occur independently.^[1] Unlike exercise-induced urticaria, which manifests as localized or generalized hives without systemic involvement, or exercise-induced asthma, which is confined to bronchoconstriction and respiratory distress, EIA encompasses the full spectrum of anaphylaxis with multi-organ effects, including dermatologic (e.g., flushing, urticaria), respiratory (e.g., wheezing, dyspnea), cardiovascular (e.g., hypotension, tachycardia), and gastrointestinal (e.g., nausea, abdominal pain) manifestations.^[6] This multisystem involvement distinguishes EIA as a more severe syndrome requiring immediate medical intervention, such as epinephrine administration.^[4] The condition was first described in 1979 in a case report of a patient experiencing anaphylactic shock following exercise after shellfish ingestion, marking the initial recognition of food-dependent EIA.^[7] By the 1980s, further studies established EIA as a unique clinical entity through observations of exercise as a standalone trigger and confirmation of mast cell involvement.^[1] EIA is exceedingly rare, accounting for an estimated 5-15% of all anaphylaxis cases, with point prevalence around 0.03% in surveys of adolescents and young adults; rates may be higher among athletes due to greater exposure and underreporting in the general population.^[8]

Epidemiology

Exercise-induced anaphylaxis (EIA) is a rare condition, with prevalence estimates varying due to underdiagnosis and limited large-scale studies. In the general population, surveys indicate a prevalence of approximately 0.03% to 0.05% for EIA among adolescents and young adults, based on questionnaire data from over 76,000 Japanese junior high school students. Food-dependent EIA (FDEIA), a subtype, shows a slightly lower prevalence of around 0.017% in similar cohorts. Globally, no precise figures exist, as EIA accounts for an estimated 2% to 15% of all anaphylactic episodes, but underreporting complicates accurate assessment.^[4] Demographically, EIA predominantly affects young adults, with a mean age of onset around 26 years (range 3–66 years), though it is most common between ages 15 and 35.^[4] Some studies report a slight female predominance, with a 2:1 female-to-male ratio in cohorts of over 200 patients, while others find no significant gender difference. It occurs more frequently among endurance athletes, such as runners and cyclists, compared to the general population, likely due to the intensity and duration of their activities like jogging or aerobics. Atopy may increase susceptibility, but EIA affects individuals across various ethnicities without consistent disparities.^[4] Geographically, most reported cases originate from temperate climates in Europe, North America, and Japan, reflecting where research and surveillance are more established. A 2023 case study from Qatar highlights potential underreporting in hot and humid regions, where environmental cofactors like extreme heat (45–49°C) and high humidity (>90%) may exacerbate symptoms but lead to fewer documented instances due to diagnostic challenges.^[4]^[9] Incidence trends for EIA have remained stable over decades, with no major increases noted in literature up to 2025. However, recognition has improved since the early 2000s, driven by greater awareness among clinicians and athletes, leading to more diagnoses without a corresponding rise in actual occurrence. Familial clustering is occasionally observed, suggesting possible genetic factors, but overall cases remain sporadic.^[4]

Clinical Presentation

Symptoms

Exercise-induced anaphylaxis (EIA) typically manifests with symptoms appearing within minutes to 30 minutes after the initiation of physical activity or immediately following its cessation in approximately 90% of cases.^[1] Initial prodromal signs often include a sensation of warmth, fatigue, and generalized pruritus, which may start in the palms, scalp, or extremities before spreading.^[10] Skin manifestations are among the most common early features, affecting over 80% of patients, and include intense pruritus (reported in 92% of cases), urticaria or hives (83-86%), flushing (70-75%), and angioedema (72-78%).^[1] These cutaneous symptoms often begin as localized itching or erythema and can rapidly generalize, contributing to the diagnostic hallmark of EIA.^[11] Respiratory symptoms occur in about 50-60% of episodes and encompass shortness of breath or dyspnea (51-59%), wheezing, chest tightness (33%), throat constriction, hoarseness, or a choking sensation (25%).^[1] These signs reflect airway involvement and can lead to stridor or laryngeal edema if progression occurs.^[10] Cardiovascular effects are prominent in severe cases, with hypotension, tachycardia, diaphoresis (32-43%), faintness, and syncope or loss of consciousness reported in up to 32% of patients.^[1] These hemodynamic changes underscore the systemic nature of the reaction and the risk of collapse during ongoing exertion.^[11] Gastrointestinal symptoms affect 25-30% of individuals and include nausea, abdominal cramping or colic, vomiting, and diarrhea.^[1] These may coincide with other manifestations and contribute to overall distress during an episode.^[10] If untreated, symptoms can escalate from prodromal and early phases (urticaria and warmth) to a fully established anaphylactic state involving multi-organ involvement, airway obstruction, and cardiovascular collapse, potentially leading to loss of consciousness.^[10] Biphasic reactions, where symptoms recur 24-48 hours later, are rare but documented in some cases.^[11] Late-phase effects, such as headache and fatigue, may persist for up to 72 hours.^[1]

Subtypes

Exercise-induced anaphylaxis (EIA) encompasses several recognized subtypes, distinguished primarily by the presence or absence of cofactors that trigger the reaction. The most prevalent variant is food-dependent exercise-induced anaphylaxis (FDEIA), which accounts for approximately 30-50% of EIA cases and requires both ingestion of a specific food and subsequent physical exertion for symptoms to manifest.^[11] In FDEIA, the reaction is IgE-mediated, involving allergens from foods such as wheat, shellfish, celery, nuts, or tomatoes that are absorbed more readily during exercise due to increased gastrointestinal permeability.^[4] Wheat-dependent EIA, a common form of FDEIA, is particularly associated with IgE reactivity to omega-5 gliadin, a major allergen in wheat gluten.^[11] Non-food-dependent EIA represents a subtype where anaphylaxis is triggered solely by exercise without any dietary cofactor, though environmental factors like temperature or humidity may contribute.^[11] This form highlights exercise as the primary physiologic stressor initiating mast cell degranulation and mediator release.^[4] Other variants include drug-dependent EIA, where medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) or alcohol act as cofactors, potentially exacerbating intestinal permeability and allergen uptake during exercise.^[11] Idiopathic EIA occurs without identifiable cofactors beyond exercise itself. A rare cholinergic subtype is linked to increases in body temperature and sweating, often presenting with smaller wheals and erythema distinct from classic EIA manifestations.^[11] FDEIA was first described in the late 1970s, with an initial report in 1979 detailing a reaction to shellfish following exercise.^[12] Wheat as a trigger in FDEIA emerged in descriptions during the 1980s, with omega-5 gliadin later identified as a key allergen in subsequent research.^[11]

Etiology and Triggers

Common Triggers

Exercise-induced anaphylaxis (EIA) is primarily precipitated by physical exertion, particularly aerobic activities of moderate to vigorous intensity. Common triggering exercises include jogging, running, swimming, tennis, dancing, bicycling, and aerobics, though lower-intensity pursuits such as brisk walking or yard work can also provoke episodes in susceptible individuals.^[4]^[13]^[6] The intensity and duration of exercise play critical roles, with symptoms often emerging after reaching a personal threshold that varies among patients, typically during the warm-up, maintenance, or cool-down phases.^[13]^[1] Dietary cofactors significantly contribute to food-dependent EIA (FDEIA), where ingestion of specific allergens shortly before or after exercise lowers the reaction threshold. Frequently implicated foods include wheat (particularly omega-5 gliadin), shellfish, nuts, peanuts, tomatoes, corn, celery, and cheese, though reactions can occur with various other items like fruits, vegetables, or even non-specific meals.^[4]^[14]^[13] Alcohol consumption can exacerbate risk by increasing intestinal permeability.^[4]^[14] Pharmacologic agents, especially nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin, act as cofactors when taken prior to exercise, promoting mast cell degranulation and anaphylaxis in predisposed individuals.^[4]^[14]^[13] Environmental conditions during exercise can further precipitate EIA, with high temperature and humidity reported in up to 64% and 32% of cases, respectively, while cold exposure or pollen (e.g., from inhalant allergens like mold or mites) may also serve as triggers.^[4]^[14]^[13] In FDEIA, a temporal pattern is characteristic, with symptoms typically manifesting within 30 minutes of exercise onset if the triggering food was consumed up to 4 hours beforehand, though reactions can occur minutes to several hours post-ingestion.^[14]^[13]^[4]

Risk Factors

A history of atopy, including personal or familial allergies such as asthma, eczema, or allergic rhinitis, significantly increases susceptibility to exercise-induced anaphylaxis (EIA), with atopy reported in approximately 50% of patients with classic EIA.^[2] This predisposition is further evidenced by the frequent coexistence of environmental allergen sensitivities, which can amplify the risk during periods of high pollen exposure, such as seasonal allergy peaks.^[1]^[4] Genetic factors contribute to vulnerability, particularly in food-dependent exercise-induced anaphylaxis (FDEIA), a subtype of EIA. Associations have been identified with specific human leukocyte antigen (HLA) alleles, including HLA-DPB1*02:01:02 in Asian populations with wheat-dependent EIA, though no single gene has been pinpointed as causative.^[15] Familial clustering has also been observed, suggesting an inherited component that may involve autosomal dominant patterns in some cases.^[6]^[11] Demographic and lifestyle elements further heighten risk. Females exhibit a higher incidence, with cohort studies showing a 2:1 female-to-male ratio among affected individuals.^[1] Onset typically occurs in adolescence or young adulthood, with a mean age of 26 years reported across cases.^[4] Participation in endurance sports, such as running or cycling, elevates susceptibility due to repeated intense physical exposure, though episodes can arise from milder activities as well.^[4]^[6] Modifiable risk factors include poorly controlled asthma, which lowers the threshold for mast cell activation during exertion, and recent viral infections, which may act as cofactors exacerbating anaphylactic responses.^[16]^[17] Managing these through optimized asthma therapy and recovery from illnesses can mitigate episode frequency. Hereditary alpha-tryptasemia, an autosomal dominant condition, has been noted as a potential genetic modifier increasing anaphylaxis risk, including in EIA cases.^[18]

Pathophysiology

Gastrointestinal Permeability

During physical exercise, blood flow is redistributed from the splanchnic circulation to active muscles and skin to meet increased metabolic demands, leading to relative gut hypoperfusion and ischemia.^[1] This reduction in splanchnic blood flow, which can decrease by up to 80% during intense exercise, compromises the integrity of the intestinal mucosa and elevates gastrointestinal permeability.^[1] The resulting ischemia disrupts tight junctions—protein complexes that seal the paracellular space between epithelial cells—allowing macromolecules to pass more readily from the gut lumen into the systemic circulation.^[19] In exercise-induced anaphylaxis, particularly the food-dependent subtype (FDEIA), this heightened permeability enables the absorption of otherwise inert dietary proteins, such as gliadin from wheat, which are typically degraded or tolerated without issue.^[20] These allergens, once systemically available, can bind to specific IgE antibodies on mast cells and basophils, initiating degranulation and anaphylactic symptoms.^[1] Clinical evidence from provocation studies in FDEIA patients demonstrates elevated serum levels of allergens like gliadin following combined food ingestion and exercise, but not with food alone, supporting the role of exercise-enhanced absorption.^[20] Animal models, including lysozyme-sensitized mice subjected to treadmill running, further confirm that exercise induces gastrointestinal leakage of allergens into the circulation, accompanied by mucosal damage and villi disruption.^[21] These permeability changes typically peak 30-60 minutes into moderate-to-intense exercise, aligning with the common onset of anaphylactic symptoms in affected individuals.^[20]

Mast Cell and Basophil Activation

In exercise-induced anaphylaxis (EIA), physical exertion acts as a cofactor that promotes the cross-linking of IgE antibodies on the surface of mast cells and basophils, leading to their degranulation and the subsequent release of preformed and newly synthesized mediators. This process is evidenced by elevated serum histamine levels observed shortly after the onset of symptoms in affected individuals, alongside morphological changes in cutaneous mast cells, such as granule membrane fusion and loss of electron density, which indicate active degranulation. The primary mediators released include histamine, which contributes to vasodilation and increased vascular permeability; leukotrienes, which promote bronchoconstriction and edema; and prostaglandins, which exacerbate smooth muscle contraction and inflammatory responses.^[22]^[23] Exercise-induced stress may also enhance enzymatic activity in tissues, particularly tissue transglutaminase, which can modify food-derived proteins—such as omega-5 gliadin in wheat-dependent cases—by cross-linking them into aggregates that function as neoallergens, thereby increasing their IgE-binding capacity and amplifying mast cell and basophil activation. This modification is hypothesized to occur under the homeostatic perturbations of exercise, facilitating greater allergen recognition even at low concentrations.^[1] Peripheral blood basophils in EIA patients demonstrate heightened sensitivity, as shown by in vitro basophil activation tests (BAT) where stimuli like gluten proteins or hydrolyzed wheat extracts elicit significantly greater degranulation (measured by CD63 expression) compared to healthy controls, with sensitivity rates up to 100% for specific glutenins. This suggests an intrinsically primed state of basophils in these individuals, responsive to exercise-mimicking conditions such as elevated osmolality, which lowers the threshold for histamine release without requiring exogenous allergens in some non-food-dependent EIA variants.^[24]^[25]^[1] Supporting evidence for mast cell involvement includes elevated serum tryptase levels during acute EIA episodes, a marker of degranulation that confirms systemic activation of these cells. In vitro studies further link simulated exercise conditions, such as hyperosmolar environments, to direct mediator release from basophils and mast cells, independent of specific allergens in certain cases, underscoring the role of physical stress in non-IgE-dependent pathways.^[26]^[1]

Hemodynamic Changes

During exercise, the body undergoes significant hemodynamic alterations, primarily involving the redistribution of blood flow to meet the demands of active tissues. Sympathetically mediated vasoconstriction in the splanchnic circulation diverts blood away from visceral organs, such as the intestines, liver, and kidneys, toward skeletal muscles, the heart, and skin.^[27] This redistribution can reduce splanchnic blood flow by up to 80% during moderate to intense exercise, leading to transient gut ischemia that exacerbates the systemic spread of inflammatory mediators.^[28] In the context of exercise-induced anaphylaxis (EIA), this shift is hypothesized to facilitate the dissemination of gut-derived allergens or sensitized immune cells to peripheral sites with more responsive mast cells, contributing to the onset of systemic responses.^[1] Transcutaneous Doppler ultrasound studies have provided direct evidence of these changes, demonstrating a marked decrease in superior mesenteric artery blood flow velocity and volume during both fasting and postprandial exercise.^[28] For instance, in healthy individuals, exercise at 70% of maximal oxygen uptake reduces mesenteric flow proportionally to the exercise intensity, with recovery occurring post-exertion but potential for prolonged hypoperfusion in susceptible cases.^[29] These hemodynamic shifts correlate with the development of hypotension in anaphylactic episodes, as reduced venous return from splanchnic pooling impairs cardiac output, amplifying circulatory collapse.^[30] The catecholamine surge accompanying exercise further influences hemodynamics through alpha- and beta-adrenergic receptor activation, promoting vasoconstriction in splanchnic beds while enhancing cardiac contractility. However, this adrenergic response may paradoxically contribute to mast cell sensitization via beta-2 receptor stimulation on certain tissues, potentially lowering the threshold for degranulation in EIA.^[31] Concurrently, intense exercise induces local tissue hypoxia and metabolic acidosis due to increased oxygen demand and lactate accumulation, which can create an inflammatory microenvironment conducive to mediator release. One case study linked exercise-induced acidosis to enhanced mast cell activity, suggesting pH changes as a contributing factor.^[27]

Diagnosis

Clinical Evaluation

The clinical evaluation of suspected exercise-induced anaphylaxis (EIA) begins with a comprehensive patient history to identify patterns linking symptoms to physical activity and potential cofactors. Clinicians should obtain detailed logs of exercise routines, including type, intensity, and duration, as well as dietary intake in the hours preceding episodes, with particular attention to foods consumed within 4-6 hours before activity onset.^[11] Timing is critical, as symptoms typically emerge within 30 minutes of exercise initiation in most cases, though delayed onset up to four hours has been reported.^[6] Recurrent episodes post-exercise serve as a key red flag, prompting urgent assessment to differentiate EIA from mimics such as heat exhaustion, which lacks allergic manifestations like pruritus or hives.^[1] Physical examination during or immediately after an episode or controlled challenge focuses on cutaneous and systemic signs. Generalized urticaria, often starting as pruritic wheals greater than 10 mm in diameter, is a hallmark finding, frequently accompanied by flushing or angioedema.^[6] Vital signs monitoring is essential, revealing potential instability such as hypotension, tachycardia, or respiratory distress indicative of progression to anaphylaxis.^[11] Diagnosis requires evidence of multi-system involvement, adapting Sampson's criteria for anaphylaxis to the exercise context, where physical activity (with or without food) acts as the provoking exposure. These criteria include acute onset of skin-mucosal involvement (e.g., urticaria or angioedema) plus respiratory compromise or reduced blood pressure, or persistent gastrointestinal symptoms with skin involvement, or hypotension after likely trigger exposure.^[32] In EIA, confirmation hinges on symptom correlation with exercise rather than isolated allergen exposure, emphasizing the need for multi-organ criteria to avoid underdiagnosis.^[1] Laboratory tests, such as serum tryptase, may support evaluation but are not diagnostic in isolation.^[11]

Diagnostic Tests

Diagnosis of exercise-induced anaphylaxis (EIA) relies on objective laboratory and provocative testing to confirm mast cell activation and reproduce symptoms under controlled conditions, distinguishing it from other forms of anaphylaxis.^[33] Serological tests play a key role in identifying mediators of anaphylaxis during acute episodes. Serum tryptase levels, measured within 1-4 hours of symptom onset, typically rise by at least 2 ng/mL plus 20% above baseline, indicating mast cell degranulation, though this criterion is not fully validated specifically for EIA.^[3] Plasma histamine concentrations also increase transiently during attacks, providing evidence of immediate mast cell activation.^[3] For food-dependent EIA (FDEIA), specific IgE testing targets allergens like omega-5 gliadin in wheat, showing high sensitivity (100%) and specificity (97%) even when total wheat IgE is negative, aiding identification of wheat as a trigger.^[3] The exercise challenge test serves as the gold standard for confirming EIA by reproducing symptoms in a supervised setting. Patients undergo treadmill exercise using protocols like the Bruce protocol for approximately 30 minutes, with or without prior ingestion of a suspected cofactor such as food, while vital signs, spirometry, and symptoms are continuously monitored.^[3] A positive test occurs if anaphylactic symptoms (e.g., urticaria, angioedema, or hypotension) develop, potentially accompanied by elevations in tryptase or histamine; however, a negative result does not exclude the diagnosis, as cofactors like nonsteroidal anti-inflammatory drugs may need inclusion for accuracy.^[33] Double-blind, placebo-controlled variants are employed when history or initial tests are inconclusive.^[33] Skin prick tests are utilized to assess IgE-mediated sensitization to potential food triggers in FDEIA cases. These involve applying allergen extracts (e.g., wheat) to the skin and pricking, with a positive result defined as a wheal greater than 3 mm compared to saline control, correlating with clinical reactivity when combined with history.^[16] Basophil activation tests (BAT) are an emerging adjunct, measuring surface markers like CD203c on basophils via flow cytometry after exposure to allergens such as gluten; they show promise in differentiating FDEIA from non-allergic reactions but have limited predictive value for certain outcomes like oral immunotherapy tolerance.^[33] All diagnostic tests, particularly challenges, must be conducted in controlled medical environments equipped with epinephrine, resuscitation facilities, and trained personnel to manage potential anaphylaxis, with contraindications in high-risk patients such as those with unstable cardiovascular disease.^[33]

Management

Acute Treatment

The acute treatment of exercise-induced anaphylaxis follows the standard protocol for anaphylaxis, emphasizing rapid intervention to reverse life-threatening symptoms. The first-line therapy is intramuscular epinephrine, administered at a dose of 0.01 mg/kg of a 1:1000 (1 mg/mL) solution, with a maximum of 0.5 mg for adults and 0.3 mg for children and adolescents, injected into the anterolateral thigh.^[34] This dose may be repeated every 5-15 minutes as needed until symptoms improve, using an epinephrine auto-injector if available.^[34] Patients should be positioned supine with legs elevated to support circulation if hypotensive, unless respiratory distress requires a semi-upright posture to maintain airway patency.^[34] Adjunctive medications are administered to manage persistent or secondary symptoms but do not replace epinephrine. Antihistamines, including H1-blockers such as diphenhydramine and H2-blockers, provide relief for cutaneous and gastrointestinal manifestations.^[34] Corticosteroids, such as methylprednisolone or prednisone, are given to potentially prevent biphasic reactions, though their immediate effects are limited.^[34] For wheezing or bronchospasm, short-acting bronchodilators like albuterol are recommended via inhalation.^[34] Supportive measures are essential to stabilize the patient during an episode. Supplemental oxygen is provided if oxygen saturation falls to 92% or below, and intravenous fluids, typically normal saline, are infused to address hypotension or shock.^[34] In cases of severe airway compromise, advanced airway management, including intubation, may be required.^[34] Emergency medical services should be activated immediately, with observation for at least 4-6 hours due to the risk of biphasic reactions.^[34] Following resolution of an episode, prescription of two epinephrine auto-injectors is mandatory for all patients diagnosed with exercise-induced anaphylaxis, in accordance with AAAAI/ACAAI guidelines, to ensure readiness for future events.^[34]

Prevention Strategies

Prevention of exercise-induced anaphylaxis (EIA) primarily relies on identifying and avoiding triggers while implementing lifestyle modifications to minimize risk during physical activity. Patients should abstain from exercise for 4 to 6 hours after consuming known trigger foods, particularly in cases of food-dependent EIA (FDEIA), to allow sufficient digestion and reduce the likelihood of anaphylactic episodes.^[14] Additionally, avoidance of nonsteroidal anti-inflammatory drugs (NSAIDs) before exercise is recommended, as they can act as cofactors exacerbating symptoms in susceptible individuals.^[35] Lifestyle adjustments play a crucial role in risk reduction. Gradual warm-up periods prior to intense exercise may help, although evidence for this is largely anecdotal and not universally supported. Exercising in controlled environments, such as avoiding extreme temperatures (hot, humid, or cold conditions), has been associated with fewer attacks in a significant proportion of patients. All individuals with EIA should carry epinephrine auto-injectors at all times and exercise with a trained partner who can recognize early symptoms and administer emergency treatment if needed.^[3]^[36] Dietary strategies focus on trigger identification and modification. Allergy testing, including skin prick tests and specific IgE assays, is essential to pinpoint causative foods and determine safe options, often supplemented by maintaining a food and symptom diary. Consuming low-residue meals before physical activity can further decrease gastrointestinal absorption of potential allergens, though this should be personalized based on individual tolerances.^[34] Medical prophylaxis is considered in select cases but lacks strong evidence for broad application. Prophylactic antihistamines (H1 and H2 blockers) may partially attenuate symptoms in some patients, particularly when taken before exercise, but they do not reliably prevent attacks. Cromolyn sodium, a mast cell stabilizer, has shown benefit in limited studies for FDEIA but is not routinely recommended due to insufficient efficacy data. Education on symptom recognition and self-management is vital for athletes and active individuals to enable prompt action.^[6]^[37] As of 2025, guidelines emphasize the development of personalized prevention plans tailored to the patient's subtype of EIA, incorporating factors such as trigger specificity and response to prophylaxis, with emerging roles for biologics like omalizumab in refractory cases following its February 2024 FDA approval for reducing allergic reactions, including anaphylaxis, from accidental food allergen exposure.^[38]^[39]^[40]

Prognosis

The prognosis for exercise-induced anaphylaxis (EIA) is generally favorable with proper identification of triggers, avoidance strategies, and acute management. Many patients experience a reduction in the frequency and severity of episodes over time, with some reporting stable or decreasing attacks averaging around 14.5 per year initially.^[1] ^[4] Mortality is rare, though untreated severe episodes can be life-threatening. Factors improving outcomes include early recognition of symptoms, adherence to prevention measures such as exercising with a partner and carrying epinephrine, and avoidance of cofactors like certain foods or medications in food-dependent EIA. With these approaches, most individuals can resume modified physical activity and maintain an active lifestyle.^[4] ^[41]

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Getting in Shape: Updates in Exercise Anaphylaxis - PMC - NIH
Sep 19, 2024 · In this article, we aim to provide the practicing clinician up to date information on several aspects of exercise induced anaphylaxis.<|separator|>
[31]
None
Below is a merged summary of the acute treatment of anaphylaxis based on the 2023 AAAAI Practice Parameters, consolidating all information from the provided segments into a comprehensive response. To maximize detail and clarity, I’ve organized key information into tables where appropriate (in CSV format for dense representation) and supplemented with narrative text for context and additional details not easily tabularized.
[32]
Severe exercise-induced anaphylaxis in a hot and humid area ... - NIH
Jul 27, 2023 · The patient was light-headed and dizzy, and unable to stand. These signs and symptoms had started after a 30-minute fast walk. There was no ...
[33]
Management and Prevention of Anaphylaxis - PMC - PubMed Central
Dec 22, 2015 · They should be counseled to exercise with a partner at all times and should carry epinephrine for autoinjection. If early signs or symptoms ...
[34]
Combined effects of food and exercise on anaphylaxis - PMC - NIH
Oct 1, 2013 · It has been shown that consumption of allergenic food followed by exercise causes FDEIAn symptoms. Intake of allergenic food or medication before exercise is a ...
[35]
Exercise induced anaphylaxis
Apr 21, 2025 · Exercise-induced anaphylaxis (EIA) is rare and has been described at all levels of physical exertion. As you know most cases are food dependent.
[36]
The management of exercise-induced anaphylaxis in a Chinese ...
Current preventative treatments include exercise avoidance, food avoidance in FDEIA, and pretreatment with medications such as antihistamines, cromolyn, or ...