Exercise-induced urticaria and anaphylaxis

The many faces of pediatric urticaria

Urticaria is a common disease that can affect individuals of all age groups, with approximately one-quarter of the population experiencing it at least once in their lifetime. Lesions characterized by erythema and itchy hives can appear anywhere on the body. These can vary in size ranging from millimeters to centimeters, and typically clear within 24 h. About 40% of patients with urticaria have accompanying angioedema, which involves localized deep tissue swelling. Urticaria usually occurs spontaneously and is classified into acute and chronic forms, with the latter referring to a condition that lasts for more than 6 weeks. The prevalence of chronic urticaria in the general population ranges from 0.5% to 5%, and it can either be inducible or spontaneous. The most common form of pediatric urticaria is acute and is usually self-limiting. However, a broad differential diagnosis should be considered in children with urticaria, particularly if they also have accompanying systemic complaints. Differential diagnoses of pediatric urticaria include chronic spontaneous urticaria, chronic inducible urticaria, serum sickness-like reaction, urticarial vasculitis, and mast cell disorders. Conditions that can mimic urticaria, including but not limited to cryopyrinopathies, hyper IgD syndrome, Periodic Fever, Aphthous Stomatitis, Pharyngitis and Adenitis (PFAPA), Tumor Necrosis Factor Receptor Associated Periodic Syndrome (TRAPs), and Schnitzler syndrome should also be considered. The many faces of pediatric urticaria can be both easy and confusing. A pragmatic approach relies on clinical foresight and understanding the various forms of urticaria and their potential mimickers. This approach can pave the way for an accurate and optimized diagnostic approach in children with urticaria.

Exercise-Induced Urticaria: A Rare Case Report

Exercise is an important part of a healthy lifestyle. However, there is a subset of the population who are allergic to exercise. Exercise-induced urticaria is a rare clinical condition, which, as the name suggests, manifests as flushing, pruritus, and hives following physical exercise. A minority of patients even develop more severe reactions including angioedema and anaphylaxis induced by exercise. Some patients are affected by certain cofactors that constitute food-dependent exercise-induced urticaria, which is relatively more common when compared to exercise-induced urticaria without other cofactors. This case report documents a healthy 27-year-old Asian male, with no other allergies or cofactors, who was diagnosed with exercise-induced urticaria. He was diagnosed based on history and a positive exercise challenge test. Avoidance of exercise is the mainstay of prophylactic treatment for this condition. Modification of physical activity proved to be effective for treating this patient. We intend to increase awareness about this rare condition through this case report and literature review.

Diagnosis of exercise-induced anaphylaxis: current insights

Exercise-induced anaphylaxis (EIAn) is defined as the occurrence of anaphylactic symptoms (skin, respiratory, gastrointestinal, and cardiovascular symptoms) after physical activity. In about a third of cases, cofactors, such as food intake, temperature (warm or cold), and drugs (especially nonsteroidal anti-inflammatory drugs) can be identified. When the associated cofactor is food ingestion, the correct diagnosis is food-dependent EIAn (FDEIAn). The literature describes numerous reports of FDEIAn after intake of very different foods, from vegetables and nuts to meats and seafood. One of the best-characterized types of FDEIAn is that due to ω5-gliadin of wheat, though cases of FDEIAn after wheat ingestion by sensitization to wheat lipid transfer protien (LTP) are described. Some pathophysiological mechanisms underlying EIAn have been hypothesized, such as increase/alteration in gastrointestinal permeability, alteration of tissue transglutaminase promoting IgE cross-linking, enhanced expression of cytokines, redistribution of blood during physical exercise leading to altered mast-cell degranulation, and also changes in the acid–base balance. Nevertheless, until now, none of these hypotheses has been validated. The diagnosis of EIAn and FDEIAn is achieved by means of a challenge, with physical exercise alone for EIAn, and with the assumption of the suspected food followed by physical exercise for FDEIAn; in cases of doubtful results, a double-blind placebo-controlled combined food–exercise challenge should be performed. The prevention of this particular kind of anaphylaxis is the avoidance of the specific trigger, ie, physical exercise for EIAn, the assumption of the culprit food before exercise for FDEIAn, and in general the avoidance of the recognized cofactors. Patients must be supplied with an epinephrine autoinjector, as epinephrine has been clearly recognized as the first-line intervention for anaphylaxis.

Cholinergic urticaria: More than a simple inducible urticaria

BACKGROUND

Cholinergic urticaria (ChU) is characterized by small wheals induced by an elevated core temperature. Its pathomechanism and various aspects of its clinical manifestations are still poorly understood. This study aimed to evaluate the spectrum of symptoms and signs of ChU in Korean patients.

METHODS

We retrospectively reviewed the medical records of patients diagnosed with ChU.

RESULTS

Among 203 patients (188 male and 15 female), 29 (14%) complained only of an itching or burning sensation without visible skin eruption. The prevalence of ChU was highest in patients in their twenties (56%), while most patients first developed their symptoms during their teens (65%). Patients with a visible skin eruption showed better responses to antihistamines than those without skin lesions.

CONCLUSIONS

Physicians should consider the varying manifestations of ChU, including cholinergic pruritus and erythema as minor variants, to provide better management of ChU.

Anaphylaxis attributed to exercise: considerations for sports medicine specialists

Anaphylaxis is an unanticipated, acute, and sometimes life-threatening systemic reaction with variable clinical presentations that is typically mediated by immunoglobulin E and causes degranulation of mast cells and basophils. The onset of symptoms can occur within minutes or hours after exposure to a known or suspected trigger, and reactions sometimes progress very rapidly, which can lead to death. One trigger of anaphylaxis in younger adults is moderately intense physical exercise, which has been termed exercise-induced anaphylaxis (EIA). Although rare, EIA should be recognized as a distinct and potentially life-threatening form of physical allergy, and is often undetected or inadequately treated. The ingestion of specific foods, including seafood, tree nuts, and wheat, or a nonspecific meal consisting of multiple food components shortly before or after physical exertion, is sometimes, but not always, the principal precipitant of EIA. This article briefly explores the current hypotheses on the role of immunoglobulin E, response mediators, and physiologic changes that bring on EIA, and discusses the current recommendations for diagnosis, including allergen challenge and laboratory testing, emergency care, and long-term prevention and patient follow-up. Accurate diagnosis of EIA is critical to providing lifesaving therapy and care plans to patients at risk. With respect to the medical management of EIA, mainstay therapy with epinephrine is described. For those with a known history of EIA, a comprehensive anaphylaxis action plan is central to successful patient management. Furthermore, patient education is necessary to heighten awareness of the signs and symptoms of EIA and appropriate strategies for allergen avoidance and self-management of anaphylactic episodes with self-injectable epinephrine.

Exercise-induced anaphylaxis: A clinical view

Exercise-induced anaphylaxis (EIA) is a distinct form of physical allergy. The development of anaphylaxis during exertion often requires the concomitant exposure to triggering factors such as intake of foods (food dependent exercise-induced anaphylaxis) or drugs prior to exercise, extreme environmental conditions. EIA is a rare, but serious disorder, which is often undetected or inadequately treated. This article summarizes current evidences on pathophysiology, diagnosis and management. We reviewed recent advances in factors triggering the release of mediators from mast cells which seems to play a pathogenetic role. A correct diagnosis is essential to avoid unnecessary restricted diet, to allow physical activity in subjects with EIA dependent from triggering factors such as food, and to manage attacks. An algorithm for diagnosing EIA based on medical history, IgE tests and exercise challenge test has been provided. In the long-term management of EIA, there is a need for educating patients and care-givers to avoid exposure to precipitating factors and to recognize and treat episodes. Future researches on existing questions are discussed.

Evaluation of different combined regimens in the treatment of cholinergic urticaria

BACKGROUND

: Cholinergic urticaria is uncommon and accounts for 10% of all young adults. To date, there is no effective therapy for cholinergic urticaria.

OBJECTIVE

: To determine the therapeutic efficacy of different drug combinations in the treatment of cholinergic urticaria.

PATIENTS AND METHODS

: The participants included in the study are in the age range of 16 to 29 years, with cholinergic urticaria of any duration as diagnosed by physicians. Patients were recruited from Asthma and Allergy Centers in Baghdad and Tikrit. The selected patients were divided randomly into 3 groups according to the treatment protocol. All patients completed screening before treatment.

RESULTS

: The study indicated that cholinergic urticaria was completely controlled in 30.4% of patients (group A) receiving 4 mg of chlorpheniramine maleate, half hour before the exercise, plus chlordiazopoxide (5 mg) and clindium bromide (2.5 mg) tablets, 3 times daily. However, cure rate was higher (83.1%) in patients (group B) receiving 4 mg of chlorpheniramine maleate (histadine), 3 times daily, plus 25 mg of maprotiline HCl (ludiomil), once daily at night. Furthermore, the complete cure rate was 85.4% in patients (group C) receiving 4 mg of chlorpheniramine maleate (histadine)3 times daily, plus 200 mg of cimetidine (tagadine), 3 times daily. The frequency of relapse was higher in group A (89%) as compared with group B (68.4%) and group C (23.5%) (P < 0.0001).

CONCLUSIONS

: Combination of H1 and H2 antagonists was more effective based on complete control of cholinergic urticaria with lower relapsing rate. However, a future placebo-controlled clinical trial taking in consideration higher H1 antagonists than we used is warranted.

Bronchial hyperresponsiveness in patients with cholinergic urticaria

BACKGROUND

Cholinergic urticaria is occasionally associated with bronchospasm, even in patients without a history of asthma; the underlying mechanism has not been elucidated.

OBJECTIVE

To evaluate bronchial hyperresponsiveness (BHR) in patients with cholinergic urticaria compared with healthy adults and patients with chronic urticaria.

METHODS

Patients with a history of cholinergic urticaria and a positive ergometric test result constitute the study group. History was reviewed and physical examination and spirometry were performed to exclude exercise-induced anaphylaxis and exercise-induced asthma. Patients with chronic urticaria and healthy volunteers were used as positive and negative controls, respectively. All 3 groups were evaluated for BHR using a methacholine challenge test.

RESULTS

Fifty-nine adults participated in the study: 30 patients with cholinergic urticaria, 15 with chronic urticaria, and 14 healthy volunteers. BHR was demonstrated in 13 of 30 patients (43%) in the study group, 1 of 15 patients with chronic urticaria (7%), and 1 of 14 healthy volunteers (7%); the observed difference was statistically significant. Further analysis of the study group demonstrated the existence of 2 subpopulations of patients with cholinergic urticaria, which were discriminated on the basis of intensity and duration of symptoms, with 96.7% accuracy. In addition, a statistically significant correlation was found between patient age and disease duration and between intensity and frequency of symptoms.

CONCLUSIONS

Evaluation of patients with cholinergic urticaria should probably include BHR. A formula based on duration and intensity of cholinergic urticaria symptoms is provided as a tool for the prediction of BHR.

Exercise-induced anaphylaxis: a serious but preventable disorder

Described for the first time approximately 30 years ago, exercise-induced anaphylaxis is a rare disorder characterized by development of a severe allergic response occurring after mild-to-strenuous physical activity. This disorder is especially important to recognize with the recent increase in physical activity and health fitness fads. A number of predisposing factors (eg, prior ingestion of particular food groups) linked to exercise-induced anaphylaxis has been outlined over the years. Mechanisms governing the condition are still being unveiled, and it is likely that one mechanism involves mast cell degranulation and inflammatory mediator generation resulting from the biochemical effects of exercise, sometimes in the presence of an ingested allergen such that wheat or shell fish. Clinical manifestations usually occur after around 10 minutes of exercise, and follow a specific sequence, starting with pruritis and widespread urticarial lesions, evolving into a more typical anaphylactic picture with respiratory distress and vascular collapse. Fatality is exceedingly rare, with only one documented case in the literature. There is an overlap of symptoms with other syndromes (such as systemic mastocytosis and cholinergic urticaria), and these should be remembered when establishing a differential. Treatment of exercise-induced anaphylaxis consists of immediate stabilization geared toward the anaphylactic response with epinephrine and anti histamines. The patient needs to be educated on preventive measures and equipped with an epinephrine autoinjector in the event of an emergency. Exercise-induced anaphylaxis remains a potentially serious disorder, and the health care provider should be aware of its clinical features and effective management strategies.

KEYWORDS

anaphylaxis; allergy; exercise; hypotension; urticaria; asthma.

Cows milk-dependent exercise-induced anaphylaxis under the condition of a premenstrual or ovulatory phase following skin sensitization

BACKGROUND

A 24 year-old woman with atopic dermatitis occasionally developed symptoms, including dyspnea and generalized urticaria, following ingestion of food containing cows milk. Similar episodes had continued, and had been treated empirically since the age of 16 years.

CASE SUMMARY

Although a skin test and IgE RAST showed positive reactions to cows milk, a provocation test with cows milk alone did not induce any symptoms. Therefore, food-dependent exercise-induced anaphylaxis (FDEIA) was suspected, but examination using various combinations of cows milk, aspirin and exercise failed to elicit any symptoms. Finally, a provocation test during the ovulatory phase with cows milk followed by aspirin and exercise evoked systemic urticaria, dyspnea and hypotension.

DISCUSSION

The symptoms against cows milk began when she took baths with bath salts containing cows milk as its main ingredient for one year at the age 15 years. Sensitization to cows milk through eczematous skin is indicated from this history. Hormonal change during a premenstrual or ovulatory phase is also an important factor for the development of FDEIA in this case.

Food-dependent exercise-induced anaphylaxis: a case related to chickpea ingestion and review

: Food-dependent exercise-induced anaphylaxis (FDEIA) is recognized as a distinct category of exercise-induced anaphylaxis (EIA) but is very likely underdiagnosed. This report describes a 41-year-old Indian woman who experienced two separate episodes of anaphylaxis while dancing after she had eaten chickpea-containing foods. The chickpea, a small legume, is a staple ingredient in culinary traditions from around the world, especially in India, the Middle East, and North Africa. Chickpea-containing dishes are also becoming more widespread in the Western world with the growing popularity of South Asian, Middle Eastern, and African cuisines. It is important to consider FDEIA in cases of unexplained anaphylaxis as reactions can occur several hours after ingesting the culprit food(s). Furthermore, no reaction occurs if a sensitized individual eats the culprit food(s) without exercising afterward; therefore, triggering foods can easily be overlooked. Current ideas on the pathophysiology, predisposing factors, workup, and treatment of FDEIA are also summarized here.

Pruritus, papules, and perspiration

BACKGROUND

The development of pruritus and papules with increased body temperature is a common clinical scenario seen in allergy practice, often leading to a diagnosis of cholinergic urticaria.

OBJECTIVE

To describe an unusual case of miliaria and its significance in the evaluation of patients with pruritic papular eruptions that occur with increased body temperature.

METHODS

An 18-year-old woman was referred to a local allergist for the evaluation of cholinergic urticaria. For the preceding 6 months, she had experienced a facial burning sensation along with diffuse pruritus accompanied by water-filled pinpoint bumps on her abdomen and extremities during exercise and with hot tub use. The lesions appeared anytime she exercised, and she reduced her workouts because of the associated discomfort. An exercise challenge was performed given the atypical description of her cutaneous symptoms.

RESULTS

After indoor aerobic exercise on a treadmill, physical examination revealed facial flushing and numerous pinpoint translucent vesicles covering her abdomen. The diagnosis of miliaria crystallina was made. Given the intense pruritus she experienced with the lesions, she was prescribed cetirizine, 10 mg once daily. However, she noted no improvement with her exercise-induced miliaria. At follow-up 1 year later, her miliaria symptoms had spontaneously resolved with no sequelae observed.

CONCLUSION

Intermittent, pruritic, papular eruptions that occur with perspiration can provide a diagnostic challenge when not present on initial examination. Although this presentation often leads to a diagnosis of cholinergic urticaria, our case illustrates that other disorders must be considered in the differential diagnosis. In these situations, exercise challenge is a valuable adjunct.

The difficulties of diagnosing food-dependent exercise-induced anaphylaxis in childhood -- a case study and review

We describe a case report of peanut and hens egg-dependent exercise-induced anaphylaxis in a 13-yr-old child, and assess the fundamental importance of careful investigations to differentiate food-dependent exercise-induced anaphylaxis from other forms of allergic reactions.

Allergic Disorders in the Athlete

Allergic diseases are common in athletes. As such, sports medicine practitioners will be involved in the management of allergic diseases on a nearly daily basis. Appreciating the wide array of allergic manifestations in this active population is essential to their accurate and efficient treatment. Although the bulk of allergic disease in athletes is mild, some allergic manifestations are far more serious and even potentially life-threatening. Aggressive and thoughtful allergy management should ensure that all athletes can continue to compete safely and at the highest level possible.

Identifying and controlling metabolic skin disorders: eczema, psoriasis, and exercise-induced urticaria

Inflammatory skin conditions can present obstacles that affect athletic participation. In eczema and psoriasis, cutaneous lesions can lead to skin breakdown, which may disqualify an athlete from participation and may also contribute to secondary infection. Adequate control of chronic skin conditions can, therefore, ensure more consistent athletic participation, and successful treatment may improve social functioning, as well. Clinicians treating athletes who have exercise-induced urticaria should be aware of the need for close observation and continual reassessment to distinguish between cholinergic urticaria and exercise-induced anaphylaxis.

Physical urticaria

Physical urticarias are a unique subgroup of chronic urticaria in which patients develop urticaria secondary to environmental stimuli. Common triggers include exercise, temperature changes, cold, heat, pressure, sunlight, vibration, and water. Systemic symptoms have occurred during severe episodes. Physical urticarias are responsible for approximately 20% to 30% of all cases of chronic urticaria. A basic knowledge of these unusual disorders is important for all healthcare providers. This article covers the following types of physical urticarias: dermatographism, cholinergic urticaria, local heat urticaria, exercise-induced anaphylaxis, vibratory angioedema, solar urticaria, and aquagenic urticaria.

Anaphylaxis: risk factors for recurrence

BACKGROUND

There are few studies on the incidence or recurrence of anaphylaxis.

OBJECTIVE

To examine the incidence of anaphylaxis and risk factors for recurrence.

METHODS

A prospective study of 432 patients referred to a community-based specialist practice in the Australian Capital Territory with anaphylaxis, followed by a survey to obtain information on recurrence.

RESULTS

Of 432 patients (48% male, 73% atopic, mean 27.4 years, SD 19.5, median 26) with anaphylaxis, 260 patients were seen after their first episode; 172 experienced 584 previous reactions. fifty-four percent of index episodes were treated in hospital. Aetiology was identified in 91.6% patients: food (61%), stinging insects (20.4%) or medication (8.3%). The minimum occurrence and incidence of new cases of anaphylaxis was estimated at 12.6 and 9.9 episodes/100,000 patient-years, respectively. Follow-up data were obtained from 304 patients (674 patient-years). One hundred and thirty experienced further symptoms (45 serious), 35 required hospitalization and 19 administered adrenaline. Accidental ingestion of peanut/tree nut caused the largest number of relapses, but the highest risk of recurrence was associated with sensitivity to wheat and/or exercise. Rates of overall and serious recurrence were 57 and 10 episodes/100 patient-years, respectively. Of those prescribed adrenaline, 3/4 carried it, 2/3 were in date, and only 1/2 patients faced with serious symptoms administered adrenaline. Five patients each developed new triggers for anaphylaxis, or re-presented with significant psychiatric symptoms.

CONCLUSION

In any 1 year, 1/12 patients who have suffered anaphylaxis will experience recurrence, and 1/50 will require hospital treatment or use adrenaline. Compliance with carrying and using adrenaline is poor. Occasional patients develop new triggers or suffer psychiatric morbidity.

[Relevance of food allergies and intolerance reactions as causes of urticaria]

Adverse reactions to food can be identified as underlying causes in various urticarial diseases. Genuine IgE-dependent allergic reactions to food are known to play a role in acute urticaria (especially in young children), in some cases of exercise-induced urticaria, and in contact urticaria. Intolerance reactions to certain foods (pseudoallergens) are recognized causes of chronic urticaria. A thorough and detailed history, keeping a urticaria diary, quantification of specific serum IgE, and skin tests as well as elimination and provocation tests can help to identify food allergy or intolerance as causes of urticaria. In urticaria patients diagnosed with food allergy or intolerance, appropriate diets will usually result in the complete remission of disease.

Pulmonary disorders and exercise

The respiratory system rarely limits exercise in the normal subject. In patients with chronic pulmonary processes or in the elite athlete, however, the respiratory system may indeed be the limiting factor. Common respiratory disorders include chest pain syndromes, cough, exercise-induced asthma, and vocal cord dysfunction. Chronic lung diseases such as asthma, COPD, and interstitial lung disease impact exercise capacity and endurance. Exercise testing can be useful to distinguish acute and chronic pulmonary causes of dyspnea during exercise, as well as to differentiate between cardiac and pulmonary causes.

Chronic urticaria

Chronic urticaria has a spectrum of clinical presentations and causes. About 50% of patients with "idiopathic" disease have histamine-releasing autoantibodies in their blood. The term autoimmune urticaria is increasingly being accepted for this subgroup of patients, in whom immunosuppressive therapies may be appropriate if conventional approaches to management are unsuccessful. This article reviews the classification, causes, and management of chronic urticaria in light of recent advances in the understanding of its etiology.

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should have up-to-date knowledge of the classification, assessment, and management of chronic urticaria and understand where the concept of autoimmune urticaria fits into existing frameworks.

Unusual urticarias

Typical urticarial lesions are transient cutaneous swellings of sudden onset, often itchy, persisting for less than 24 hours and resolving to leave normal appearing skin. Angioedema lesions are similar subcutaneous lesions. Atypical urticarias persist for longer than 24 hours, may be painful and bruised in appearance and accompanied with severe systemic symptoms. Conditions where prolonged weals are present include delayed pressure urticaria and urticarial vasculitis. These conditions do not respond well to antihistamine therapy. In delayed pressure urticaria, weals appear after a delay of hours at sites of sustained pressure on the skin and occur in association with ordinary chronic 'idiopathic' urticaria. Weals of urticarial vasculitis show histological features of venulitis, and can be accompanied by arthralgia and abdominal pain. Rarely, the condition is due to infective or autoimmune disease. Urticarial diseases, sometimes with features of urticarial vasculitis, and with associated systemic features include Schnitzler's Syndrome, Still's disease and Muckle-Wells syndrome. The latter syndrome is linked with chromosome 1q44, as is autosomal dominant cold urticaria, an unusual physical urticaria. Persistent cholinergic erythema, a variant of cholinergic urticaria, has been mistaken for a drug eruption or cutaneous mastocytosis. Rarely, food and exercise induced urticaria and anaphylaxis occur when exercise follows a specific food or any meal within a few hours. The early stages of inflammatory disease may be mistaken for urticaria and angioedema, but lesions usually persist for longer than 48 hours and are accompanied by epidermal changes.

Food-dependent exercise-induced anaphylaxis

Food-dependent exercise-induced anaphylaxis (FDEIA) is a specific variant of exercise-induced anaphylaxis that requires both vigorous physical activity and the ingestion of specific foods within the preceding several hours. When patients present to the emergency department (ED) with allergic reactions, careful history regarding these 2 factors is required to establish the correct diagnosis. Correct diagnosis of FDEIA will allow patients to take control of their lifestyles and avert repeated events and ED visits. Two cases of FDEIA are presented, and the diagnosis, pathophysiology and therapy of food-dependent exercise-induced anaphylaxis are reviewed.

Aspirin enhances the induction of type I allergic symptoms when combined with food and exercise in patients with food-dependent exercise-induced anaphylaxis

We examined the effect of aspirin as a substitute for exercise in inducing urticaria/anaphylaxis in three patients with food-dependent exercise-induced anaphylaxis (FDEIA). Two of the patients had specific IgE antibodies to wheat and the other had antibodies to shrimp. Administration of aspirin before ingestion of food allergens induced urticaria in one patient and urticaria and hypotension in another, while aspirin alone or food alone elicited no response. The third patient developed urticaria only when he took all three items, i.e. aspirin, food and additional exercise, whereas provocation with any one or or two of these did not induce any symptoms. These findings suggest that aspirin upregulates type I allergic responses to food in patients with FDEIA, and further shows that aspirin synergizes with exercise to provoke symptoms of FDEIA. This is the first report of a synergistic effect of aspirin in inducing urticaria/anaphylaxis, which was confirmed using challenge tests in patients with FDEIA.

Rye gamma-70 and gamma-35 secalins and barley gamma-3 hordein cross-react with omega-5 gliadin, a major allergen in wheat-dependent, exercise-induced anaphylaxis

Patients with wheat-dependent, exercise-induced anaphylaxis experience severe allergic reactions when exercising after ingestion of wheat. The major wheat allergen associated with these reactions is a omega-5 gliadin, and patients following a gluten-free diet have remained free of symptoms. The aim of this study was to examine whether allergens cross-reacting with wheat omega-5 gliadin are present in rye, barley and oats. Sera from 23 adult patients with wheat-dependent, exercise-induced anaphylaxis were examined. Cereal allergens cross-reacting with wheat omega-5 gliadin were identified by immunoblot inhibition. The cross-reactive allergens were purified by gel filtration and reversed-phase chromatography and submitted to amino acid sequencing. Cross-reactivity was further studied by IgE ELISA and ELISA inhibition, and in vivo reactivity by skin prick testing. In immunoblotting rabbit anti-omega-5 gliadin antibodies bound to 70 kDa and 32 kDa proteins in rye and a 34-kDa protein in barley, but not to proteins in oats. N-terminal sequencing identified these proteins as rye gamma-70 secalin, rye gamma- 35 secalin and barley gamma-3 hordein, correspondingly. In ELISA 21/23 (91%) patients with wheat-dependent, exercise-induced anaphylaxis showed IgE antibodies to purified gamma-70 secalin, 19/23 (83%) to gamma-35 secalin and 21/23 (91%) to gamma-3 hordein. In ELISA inhibition omega-5 gliadin inhibited over 90% of the IgE binding of pooled patient sera to solid-phase gamma-secalins and gamma-3 hordein. Skin prick testing gave positive reactions to gamma-70 secalin in 10/15 (67%) patients, to gamma-35 secalin in 3/15 (20%) patients and to gamma-3 hordein in 7/15 (47%) patients. The results of this study show that gamma-70 and gamma-35 secalins in rye and gamma-3 hordein in barley cross-react with omega-5 gliadin, a major allergen in wheat-dependent, exercise-induced anaphylaxis. These findings suggest that also rye and barley may elicit symptoms in patients with wheat-dependent, exercise-induced anaphylaxis.

Acute and chronic urticaria. Challenges and considerations for primary care physicians

Urticaria and angioedema are common dermatologic problems seen by primary care physicians. A carefully taken history, physical examination, specific tests, and skin biopsy often provide useful diagnostic information. In patients with chronic urticaria, urticarial vasculitis and diseases that mimic urticaria need to be ruled out. A variety of treatment options are available for patients with urticaria and urticarial vasculitis. Pharmacologic therapy is useful when the specific cause is undetermined. When a trigger has been identified, the patient must avoid exposure to it. Patient education is an important component of management and should include instructions on crisis management, particularly for patients who have angioedema or a tendency for anaphylaxis.

Exercise-induced anaphylaxis (EIA)

EIA is a unique physical allergy with increasing incidence as the exercising population increases. Clinical features are indistinguishable from IgE-mediated anaphylaxis in which the offending allergens are known (food or insect stings). Recognition of the association with exercise is crucial. A wide variety of exercises can induce the symptoms, including brisk walking. Symptoms may not be always reproduced by the same amount and type of exercise in a given patient suggesting that associated factors are also needed. Food is an associated factor recognized with increasing frequency, and in the last 5 yr, wheat has been the most frequently associated. Avoidance of the known associated factors, such as food or nonsteroidals, induces a long-lasting remission of EIA. Treatment does not differ from that of anaphylaxis of any other cause. General recommendations for patients with EIA include avoidance of exercise 4-6 h after eating, avoidance of aspirin and nonsteroidals before exercise, and avoidance of all associated conditions known to trigger attacks in each particular patient. Discontinuation of exercise at the earliest warning symptom is critical.

Control of cAMP in lung endothelial cell phenotypes. Implications for control of barrier function

Pulmonary microvascular endothelial cells (PMVECs) form a more restrictive barrier to macromolecular flux than pulmonary arterial endothelial cells (PAECs); however, the mechanisms responsible for this intrinsic feature of PMVECs are unknown. Because cAMP improves endothelial barrier function, we hypothesized that differences in enzyme regulation of cAMP synthesis and/or degradation uniquely establish an elevated content in PMVECs. PMVECs possessed 20% higher basal cAMP concentrations than did PAECs; however, increased content was accompanied by 93% lower ATP-to-cAMP conversion rates. In PMVECs, responsiveness to beta-adrenergic agonist (isoproterenol) or direct adenylyl cyclase (forskolin) activation was attenuated and responsiveness to phosphodiesterase inhibition (rolipram) was increased compared with those in PAECs. Although both types of endothelial cells express calcium-inhibited adenylyl cyclase, constitutive PMVEC cAMP accumulation was not inhibited by physiological rises in cytosolic calcium, whereas PAEC cAMP accumulation was inhibited 30% by calcium. Increasing either PMVEC calcium entry by maximal activation of store-operated calcium entry or ATP-to-cAMP conversion with rolipram unmasked calcium inhibition of adenylyl cyclase. These data indicate that suppressed calcium entry and low ATP-to-cAMP conversion intrinsically influence calcium sensitivity. Adenylyl cyclase-to-cAMP phosphodiesterase ratios regulate cAMP at elevated levels compared with PAECs, which likely contribute to enhanced microvascular barrier function.

A novel wheat gliadin as a cause of exercise-induced anaphylaxis

BACKGROUND

Food-dependent, exercise-induced anaphylaxis is a severe form of allergy; the reaction is caused by ingestion of a specific food before exercise. This disorder often escapes diagnosis because neither the ingested food nor the exercise alone induces the symptoms.

OBJECTIVE

The aim of the study was to characterize the allergens involved in wheat-dependent, exercise-induced anaphylaxis and to describe the clinical outcome in a series of 18 adult patients.

METHODS

All 18 patients had experienced recurrent episodes of generalized urticaria during exercise, 17 patients in association with collapse and 15 patients with an anaphylactic reaction. The symptoms appeared only when the patients had eaten food containing wheat before exercise. Wheat allergens were detected by immunoblotting, purified by gel filtration and reversed-phase chromatography, and subjected to N-terminal sequencing. The IgE-binding ability of the purified proteins was studied by ELISA, and their in vivo reactivity was studied by skin prick testing.

RESULTS

IgE antibodies from pooled patient sera were bound to 65-kd and 40-kd wheat proteins in immunoblotting. The 65-kd allergen was a previously undescribed wheat protein, showing 61% sequence identity to gamma-gliadin, whereas the 40-kd allergen had 100% identity to alpha-gliadin. In ELISA, all 18 patients showed elevated IgE levels to the novel gamma-like gliadin, and 13 of the patients showed elevated IgE levels to the alpha-gliadin. None of the 54 control subjects with wheat allergy, urticaria, or coeliac disease had IgE antibodies to the gamma-like gliadin. The in vivo reactivity of the gamma-like gliadin was verified by positive skin prick test responses in all of the 15 patients who were tested. During the follow-up on a gluten-free or wheat-free diet, 3 patients experienced reactions after having unknowingly eaten wheat before exercise, but all the other patients who were adhering to the diet remained symptom-free.

CONCLUSION

This study shows that wheat is a frequent cause of food-dependent, exercise-induced anaphylaxis and suggests that the major allergen is a previously undescribed gamma-like gliadin. For screening of this life-threatening allergy, we recommend skin prick testing with crude gliadin and we recommend a gluten-free diet for treatment.

ECG Quiz: Flushing, Paresthesias, and Difficulty Swallowing After a Run

A 45-year-old veteran runner, while on a summer vacation in Martha's Vineyard, went for his usual 5-mile jog in 80 degrees F weather. Two minutes after completing the run, his vision blurred and he became lightheaded. He had difficulty swallowing and noted tingling in his hands and arms and generalized flushing. He felt no chest pain, but his facial and arm muscles felt "distorted."