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. It is a rapidly evolving, multisystem process involving the integumentary, pulmonary, gastrointestinal, and cardiovascular systems. Anaphylaxis and angioedema are serious disorders that can lead to fatal airway obstruction and culminate in cardiorespiratory arrest, resulting in hypoxemia and/or shock. Often, these disorders can be appropriately managed in an outpatient setting; however, these conditions can be severe enough to warrant evaluation of the patient in the ED and in some cases, hospitalization, and management in an ICU. Reports suggest that underdiagnosis and undertreatment of anaphylaxis are common. Several new syndromes have been described recently including bird-egg, pork-cat, delayed allergy to mammalian meat and a diverse group of mast cell activation disorders. Conditions such as postural orthostatic tachycardia syndrome, carcinoid syndrome, Munchausen stridor, and factitious anaphylaxis can present similarly and need to be included in the differential diagnosis. Anaphylaxis is a clinical diagnosis, but plasma tryptase and urinary histamine levels are often elevated, allowing diagnostic confirmation; however, diagnostic testing should not delay treatment as results may not be immediately available. The sine qua non of treatment is avoidance of any known triggers and epinephrine, which should never be delayed if this disorder is suspected. Secondary treatments include fluids, bronchodilators, antihistamines, and glucocorticoids. Patients with cardiopulmonary arrest or airway or vascular compromise require mechanical ventilation, vasopressors, and other advanced life support in the ICU.
Annals of allergy, asthma & immunology : official publication of the American College of Allergy, Asthma, & Immunology •
Although meat is a main source of proteins in western diets, little information is available regarding allergy to vertebrate meats or the allergens implicated in these reactions. To evaluate the in vitro IgE antibody response to different vertebrate meats in suspected meat-allergic subjects, as well as the possible role of tropomyosin in meat allergy and to analyze the cross-reactivity between vertebrate meats and the effect of heating on the IgE-binding to meat proteins. Fifty-seven sera from suspected meat-allergic subjects were tested by grid blot to extracts of beef, lamb, pork, venison, chicken, and turkey and to four mammalian tropomyosins of different origins. Meat-allergic subjects have IgE antibodies to proteins in different mammalian meats (43/57 subjects); cross-reactivity with avian meat was limited: less than 50% (19/43) of meat positive sera reacted to chicken. In contrast, most of the poultry-positive sera also reacted to different mammalian meats. In general, there was stronger IgE reactivity to raw meats in comparison to cooked meats; an exception was six cases in which IgE reactivity to cooked poultry was stronger. Weak IgE reactivity to tropomyosin was detected in only 2/57 sera tested. Suspected meat-allergic subjects have serum IgE directed to meat proteins. In vitro cross-reactivity among mammalian meats appears to be important, while cross-reactivity to poultry is limited indicating mammalian-specific proteins. Although cooking in general denatures meat proteins rendering them less allergenic, in some cases the process of cooking may result in the formation of new allergenic moieties. The muscle protein tropomyosin is not an important vertebrate meat allergen.
