History
Anaphylaxis is an acute multiorgan system reaction. The most common organ systems involved include the cutaneous, respiratory, cardiovascular, and gastrointestinal (GI) systems. In most studies, the frequency of signs and symptoms of anaphylaxis is grouped by organ system.
Anaphylactic reactions almost always involve the skin or mucous membranes. Greater than 90% of patients have some combination of urticaria, erythema, pruritus, or angioedema. In the Memphis study, for example, 87% of patients had urticaria and/or angioedema.[29] Other retrospective studies have reported similar rates of mucocutaneous involvement.
Children, however, may be different. An Australian study evaluated 57 children under age 16 years who presented to a pediatric emergency department (ED) over a three-year period. Cutaneous features were noted in 82.5%, whereas 95% had respiratory symptoms. The reasons why a lack of dermal findings would be more common in children than in adults are not well understood.
The upper respiratory tract commonly is involved, with complaints of nasal congestion, sneezing, or coryza. Cough, hoarseness, or a sensation of tightness in the throat may presage significant airway obstruction. Eyes may itch and tearing may be noted. Conjunctival injection may occur.
Dyspnea is present when patients have bronchospasm or upper airway edema. Hypoxia and hypotension may cause weakness, dizziness, or syncope. Chest pain may occur due to bronchospasm or myocardial ischemia (secondary to hypotension and hypoxia). GI symptoms of cramplike abdominal pain with nausea, vomiting, or diarrhea also occur but are less common, except in the case of food allergy.
The Memphis study reported dyspnea in 59%, syncope or lightheadedness in 33%, and diarrhea or abdominal cramps in 29%.[29] Other studies have reported similar findings.
Initially, patients often describe a sense of impending doom, accompanied by pruritus and flushing. This can evolve rapidly into the following symptoms, broken down by organ system:
Cutaneous/ocular - Flushing, urticaria, angioedema, cutaneous and/or conjunctival pruritus, warmth, and swelling
Respiratory - Nasal congestion, rhinorrhea, throat tightness, wheezing, shortness of breath, cough, hoarseness
Cardiovascular - Dizziness, weakness, syncope, chest pain, palpitations
Gastrointestinal - Dysphagia, nausea, vomiting, diarrhea, bloating, cramps
Neurologic - Headache, dizziness, blurred vision, and seizure (very rare and often associated with hypotension)
Other - Metallic taste, feeling of impending doom
Symptoms usually begin within 5-30 minutes from the time the culprit antigen is injected but can occur within seconds. If the antigen is ingested, symptoms usually occur within minutes to 2 hours. In rare cases, symptoms can be delayed in onset for several hours. Parenteral administration of monoclonal antibodies and oral ingestion of mammalian meat (eg, beef, pork, lamb) have recently been reported to be potential causes for anaphylaxis characterized by delayed onset.[52, 53, 54, 55, 56] It must be remembered that anaphylaxis can begin with relatively minor cutaneous symptoms and rapidly progress to life-threatening respiratory or cardiovascular manifestations. In general, the more rapidly anaphylaxis develops after exposure to an offending stimulus, the more likely the reaction is to be severe.
A thorough history remains the best test to determine a causative agent. For recurrent idiopathic episodes, a patient diary may be helpful to implicate specific foods or medications, including over-the-counter (OTC) products.
HistoryAnaphylaxis is an acute multiorgan system reaction. The most common organ systems involved include the cutaneous, respiratory, cardiovascular, and gastrointestinal (GI) systems. In most studies, the frequency of signs and symptoms of anaphylaxis is grouped by organ system.Anaphylactic reactions almost always involve the skin or mucous membranes. Greater than 90% of patients have some combination of urticaria, erythema, pruritus, or angioedema. In the Memphis study, for example, 87% of patients had urticaria and/or angioedema.[29] Other retrospective studies have reported similar rates of mucocutaneous involvement.Children, however, may be different. An Australian study evaluated 57 children under age 16 years who presented to a pediatric emergency department (ED) over a three-year period. Cutaneous features were noted in 82.5%, whereas 95% had respiratory symptoms. The reasons why a lack of dermal findings would be more common in children than in adults are not well understood.The upper respiratory tract commonly is involved, with complaints of nasal congestion, sneezing, or coryza. Cough, hoarseness, or a sensation of tightness in the throat may presage significant airway obstruction. Eyes may itch and tearing may be noted. Conjunctival injection may occur.Dyspnea is present when patients have bronchospasm or upper airway edema. Hypoxia and hypotension may cause weakness, dizziness, or syncope. Chest pain may occur due to bronchospasm or myocardial ischemia (secondary to hypotension and hypoxia). GI symptoms of cramplike abdominal pain with nausea, vomiting, or diarrhea also occur but are less common, except in the case of food allergy.The Memphis study reported dyspnea in 59%, syncope or lightheadedness in 33%, and diarrhea or abdominal cramps in 29%.[29] Other studies have reported similar findings.Initially, patients often describe a sense of impending doom, accompanied by pruritus and flushing. This can evolve rapidly into the following symptoms, broken down by organ system:Cutaneous/ocular - Flushing, urticaria, angioedema, cutaneous and/or conjunctival pruritus, warmth, and swellingRespiratory - Nasal congestion, rhinorrhea, throat tightness, wheezing, shortness of breath, cough, hoarsenessCardiovascular - Dizziness, weakness, syncope, chest pain, palpitationsGastrointestinal - Dysphagia, nausea, vomiting, diarrhea, bloating, crampsNeurologic - Headache, dizziness, blurred vision, and seizure (very rare and often associated with hypotension)Other - Metallic taste, feeling of impending doomSymptoms usually begin within 5-30 minutes from the time the culprit antigen is injected but can occur within seconds. If the antigen is ingested, symptoms usually occur within minutes to 2 hours. In rare cases, symptoms can be delayed in onset for several hours. Parenteral administration of monoclonal antibodies and oral ingestion of mammalian meat (eg, beef, pork, lamb) have recently been reported to be potential causes for anaphylaxis characterized by delayed onset.[52, 53, 54, 55, 56] It must be remembered that anaphylaxis can begin with relatively minor cutaneous symptoms and rapidly progress to life-threatening respiratory or cardiovascular manifestations. In general, the more rapidly anaphylaxis develops after exposure to an offending stimulus, the more likely the reaction is to be severe.A thorough history remains the best test to determine a causative agent. For recurrent idiopathic episodes, a patient diary may be helpful to implicate specific foods or medications, including over-the-counter (OTC) products.
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