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Involvement of body organ systems in anaphylaxis varies among patients, and even in the same patient from one allergic reaction to another. However, there are general patterns regarding organ system involvement and signs and symptoms associated with anaphylaxis.1-3
Most often, allergic reactions involve the skin (80%-90%) and the respiratory tract (70%).3,4 Less often, allergic reactions involve the GI tract (30%-45%), the cardiovascular system (10%-45%) and the central nervous system (10%-15%).3,4 See Table 1. Symptoms involving the throat, lungs or heart can potentially be life-threatening and should not be ignored. See Table 2.3,5
|Skin||Airway*||Central Nervous System||Cardiovascular System*||GI Tract|
|80-90% of reactions||70% of reactions||10-15% of reactions||10-45% of reactions||30-45% of reactions|
|Hives (urticarial), itching (pruritus), flushing||Larynx: pruritus and tightness in throat; dysphonia and hoarseness||Uneasiness, throbbing headache, dizziness, confusion, tunnel vision||Chest pain, hypotension, tachycardia, weak pulse, dizziness, fainting||Nausea, cramping, abdominal pain, vomiting, diarrhea|
|Mucosal tissue: pruritus and swelling of lips, tongue, uvula/palate||Lung: dyspnea, chest tightness, wheezing/bronchospasm|
*Potentially life-threatening symptoms.
|Pruritus and tightness in the throat||Dyspnea||Chest pain|
In patients who have experienced anaphylaxis, it is important to confirm the allergic trigger or triggers.3,6 A detailed history of prior exposures and resulting allergic reactions can identify specific allergic triggers that should be avoided in order to prevent recurrences of anaphylaxis.2,3,6
Determining the nature of the symptoms during previous anaphylactic reactions is also important. It is critical to ask the patient if there was2:
- Evidence of skin manifestations, particularly angioedema, flushing, pruritus or urticaria
- Upper or lower airway obstruction
- Nausea, vomiting, diarrhea or other GI symptoms
- Syncope/presyncopal symptoms
In addition to the patient’s history, several tests are available to help identify allergic triggers of anaphylaxis, including skin tests, in vitro tests and challenge tests.3 These tests are described in Table 3.
|In vitro tests|
Anaphylaxis diagnosis criteria
Major risk factors for a recurrent anaphylactic reaction include a history of previous anaphylaxis, exposure to allergic triggers and atopy.2 However, the severity of previous allergic reactions is not always indicative of the severity of future reactions.2,6,10
There are factors that increase the risk of anaphylaxis, such as exposure to known allergens, as well as factors that may increase the risk of a severe anaphylactic reaction, such as concomitant diseases and medications that hinder a patient from recognizing the signs and symptoms of anaphylaxis.3 A complete description of these risk factors can be found in Tables 5 and 6.
Exposure to certain allergens increases the risk of triggering an anaphylactic reaction for those who are allergic, including:
The following concomitant diseases are associated with an increased risk of a severe anaphylactic reaction:
In patients of any age, concomitant diseases hampering recognition of signs and symptoms of anaphylaxis may place patients at an increased risk of a more severe anaphylactic reaction. Such diseases include:
|Concurrent medication or chemical use|
In patients of any age, concurrent medications and chemicals hampering recognition of signs and symptoms of anaphylaxis may place patients at an increased risk of anaphylaxis. Such medications and/or chemicals include:
Medications that may increase the severity of anaphylactic reactions and make them more difficult to treat include:
- Dinakar C. Anaphylaxis in children: current understanding and key issues in diagnosis and treatment. Curr Allergy Asthma Rep. 2012;12(6):641-649.
- Lieberman P, Nicklas RA, Randolph C, et al. Anaphylaxis—a practice parameter update 2015. Ann Allergy Asthma Immunol. 2015;115(5):341-384.
- Simons FE. Anaphylaxis. J Allergy Clin Immunol. 2010;125(2)(suppl 2):S161-S181.
- Simons FE. Anaphylaxis: recent advances in assessment and treatment. J Allergy Clin Immunol. 2009;124(4):625-636.
- Volcheck GW. Clinical Allergy: Diagnosis and Management. Rochester, MN: Mayo Foundation for Medical Education and Research; 2009.
- Simons FE, Ardusso LR, Bilὸ MB, et al; World Allergy Organization. World Allergy Organization guidelines for the assessment and management of anaphylaxis. World Allergy Organ J. 2011;4(2):13-37.
- Bousquet J, Heinzerling L, Bachert C, et al. Practical guide to skin prick tests in allergy to aeroallergens. Allergy. 2012;67(1):18-24.
- Johansson SG. ImmunoCAP specific IgE test: an objective tool for research and routine allergy diagnosis. Expert Rev Mol Diagn. 2004;4(3):273-289.
- Sampson HA, Muñoz-Furlong A, Campbell RL, et al. Second symposium on the definition and management of anaphylaxis: summary report—Second National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network symposium. J Allergy Clin Immunol. 2006;117(2):391-397.
- Boyce JA, Assa’ad A, Burks AW, et al. Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel. J Allergy Clin Immunol. 2010;126(6):S1-S58.