Allergy & Clinical Immunology
Canadian Society of Allergy and Clinical Immunology
Last updated: May 2025
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The presence of IgG to a specific food indicates previous exposure not hypersensitivity. The use of methods other than serum-specific IgE evaluation or skin prick testing in diagnosing allergies is not proven and can result in inappropriate diagnosis and treatment.
Sources:
Bernstein IL, et al. Allergy diagnostic testing: an updated practice parameter. Ann Allergy Asthma Immunol. 2008 Mar;100:S1–148. PMID: 18431959.
Carr S, et al. CSACI Position statement on the testing of food-specific IgG. Allergy Asthma Clin Immunol. 2012 Jul;8(1):12. PMID: 22835332.
Cox L, et al. Pearls and pitfalls of allergy diagnostic testing: report from the American College of Allergy, Asthma and Immunology/ American Academy of Allergy, Asthma & Immunology Specific IgE Test Task Force. Ann All Asthma Immunol. 2008 Dec; 101(6):580–592. PMID: 19119701.
Stapel SO, et al. Testing for IgG4 against foods is not recommended as a diagnostic tool: EAACI Task Force Report. Allergy. 2008 Jul;63(7):793-796. PMID: 18489614.
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Specific IgE to foods may be detectable when the patient is clinically tolerant. Frequent false positives lead to incorrect diagnosis of food allergies and unnecessary dietary restrictions. Appropriate diagnosis and treatment of allergies requires specific IgE testing (either skin or blood tests) based on the patient’s clinical history of signs and symptoms to optimize both cost effectiveness and patient care.
Sources:
Bernstein IL, et al. Allergy diagnostic testing: an updated practice parameter. Ann Allergy Asthma Immunol. 2008 Mar;100:S1–148. PMID: 18431959.
NIAID-Sponsored Expert Panel: Boyce JA, 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 Dec;126(6 Suppl):S1-58. PMID: 21134576.
Sicherer SH, et al. Allergy Testing in Childhood: Using Allergen-Specific IgE Tests, Pediatrics. 2012 Jan;129(1):193-197. PMID: 22201146.
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Epinephrine is the drug of choice to treat anaphylaxis. Overuse of antihistamines in anaphylaxis is associated with increased morbidity. H1 antagonists serve as second-line treatment for cutaneous non-life-threatening symptoms such as urticaria but should not be used in place of epinephrine. They do not alleviate or prevent cardiovascular or respiratory symptoms of anaphylaxis and can delay the administration of epinephrine, increasing the risk of potential consequences such as disability or fatality. Prompt use of epinephrine is important for the emergency treatment of anaphylaxis.
Sources:
Andreae DA, et al. Should Antihistamines be Used to Treat Anaphylaxis? BMJ. 2009 Jul;339:b2489.
Cox L, et al. Allergen immunotherapy: a practice parameter third update, J Allergy Clin Immunol. 2011 Jan;127(1 Suppl):s1–55. PMID: 21122901.
Fineman SM. Optimal Treatment of Anaphylaxis: Antihistamines Versus Epinephrine. Postgrad Med. 2014 Jul;126(4):73-81. PMID: 25141245.
Finnerup NB, et al. Pharmacotherapy for neuropathic pain in adults: a systematic review and meta-analysis. Lancet Neurol. 2015 Feb;14(2):162-73. PMID: 25575710.
Kemp SF, et al. Epinephrine the drug of choice for anaphylaxis. A statement of the World Allergy Organization. Allergy. 2008 Aug;63(8):1061–70. PMID: 18691308.
Lieberman P, et al. Anaphylaxis – a practice parameter update 2015. Ann Allergy Asthma Immunol. 2015 Nov;115(5):341-84. PMID: 26505932.
Sheikh A, et al. H1-antihistamines for the treatment of anaphylaxis. Allergy. 2007 Aug;62(8):830–837. PMID: 17620060.
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Findings on a patient’s history and physical exam such as cough, wheeze and dyspnea may be caused by many conditions, including asthma. When the diagnosis of current or persistent asthma is suspected it must be confirmed with objective testing, as up to one third of patients with suspected asthma show no objective evidence when later tested and may have went into sustained clinical remission or never had asthma. Misdiagnosis leads to delayed treatment of the underlying condition and unnecessary exposure to medication side effects. Objective methods of confirming the diagnosis of asthma in patients in whom asthma is suspected should be used such as spirometry, methacholine challenge, exercise challenge or peak flow variability. These tests may be normal when on treatment.
Sources:
Aaron SD, et al. Reevaluation of Diagnosis in Adults With Physician-Diagnosed Asthma. JAMA. 2017 Jan;317(3):269-279. PMID: 28114551.
Bateman ED, et al. Global strategy for asthma management and prevention: GINA executive summary. Eur Respir J. 2008 Jan;31:143–178. PMID: 18166595.
Dahl R, et al. Intranasal and inhaled fluticasone propionate for pollen-induced rhinitis and asthma. Allergy. 2005 Jul;60(7):875-81. PMID: 15932376.
Global Initiative for Asthma. Global Strategy for Asthma Management and Prevention. [Internet]. 2018 [cited 2018 July 30].
Lougheed MD, et al. Canadian Thoracic Society 2012 guideline update: Diagnosis and management of asthma in preschoolers, children and adults. Can Respir J. 2012;19(2):127-164. PMID: 22536582.
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Viral infections are the primary cause of acute rhinosinusitis, whereby only 0.5% to 2% develop into bacterial infections. Most cases of clinically diagnosed acute rhinosinusitis improve without treatment within two weeks. For those with uncomplicated acute rhinosinusitis, who have a mild illness, observation without use of antibiotics is recommended. If a decision is made to treat, clinicians should prescribe amoxicillin as first-line antibiotic therapy for most cases of acute rhinosinusitis.
Sources:
Ahovuo-Saloranta A, et al. Antibiotics for acute maxillary sinusitis in adults. Cochrane Database Syst Rev. 2014 Feb;(2):CD000243. PMID: 24515610.
Peters AT, et al. Diagnosis and management of rhinosinusitis: a practice parameter update. Ann Allergy Asthma Immunol.2014 Oct;113(4):347-385. PMID: 25256029.
Rosenfeld RM, et al. Clinical practice guideline (update): adult sinusitis. Otolaryngol Head Neck Surg. 2015 Apr;152(2 Suppl):S1-S39. PMID: 25832968.
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Abnormal images of the sinuses cannot stand alone as diagnostic evidence of bacterial rhinosinusitis. Radiologic changes such as mucosal thickening are present in most cases of acute viral infections of the upper respiratory tract when sensitive detection methods such as CT scanning are used. Incidental findings of mucosal thickening can also be seen in a high percentage of asymptomatic individuals.
Sources:
Desrosiers M, et al. Canadian clinical practice guidelines for acute and chronic rhinosinusitis. Allergy Asthma Clin Immunol. 2011; 7(1): 2. PMID: 21310056.
Kirsch CF, et al. Expert Panel on Neurologic Imaging: ACR Appropriateness Criteria® for Sinonasal Disease. J Am Coll Radiol. 2017 Nov;14(11S):S550-S559. PMID: 29101992.
Rosenfeld RM, et al. Clinical practice guideline (update): adult sinusitis. Otolaryngol Head Neck Surg. 2015 Apr;152(2 Suppl):S1-S39. PMID: 25832968.
Young J, et al. The clinical diagnosis of acute bacterial rhinosinusitis in general practice and its therapeutic consequences. J Clin Epidemiol. 2003;56:377–384. PMID: 12767415.
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While a history of penicillin allergy is self-reported by approximately 6-25% of patients, most are able to tolerate penicillin. In those with penicillin allergy, it may remit over time. Patients deemed ‘penicillin-allergic’ are more likely to: be treated with broad-spectrum alternative antibiotics (such as vancomycin, quinolones and clindamycin); experience longer hospital stays; and develop complications such as infections with methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and Clostridium difficile. IgE-mediated penicillin allergy can be evaluated through skin testing or graded oral challenge.
Sources:
Abrams EM, et al. Delabeling penicillin allergy: Is skin testing required at all? J Allergy Clin Immunol Pract. 2019 Apr;7(4):1377. PMID: 30961847.
Castells M, et al. Penicillin Allergy. N Engl J Med. 2019 Dec 12;381(24):2338-2351. PMID: 31826341.
Chen JR, et al. A Proactive Approach to Penicillin Allergy Testing in Hospitalized Patients. J Allergy Clin Immunol Pract. 2017 May;5(3):686-693. PMID: 27888034.
Macy E, et al. Healthcare Use and Serious Infection Prevalence Associated with Penicillin “Allergy” In Hospitalized Patients: A Cohort Study. J Allergy Clin Immunol. 2014 Mar;133(3):790-6. PMID: 24188976.
Park MA, et al. Safety and effectiveness of a preoperative allergy clinic in decreasing vancomycin use in patients with a history of penicillin allergy. Ann Allergy Asthma Immunol. 2006 Nov;97(5):681–687. PMID: 17165279.
Penicillin Allergy in Antibiotic Resistance Workgroup. Penicillin Allergy Testing Should Be Performed Routinely in Patients with Self-Reported Penicillin Allergy. J Allergy Clin Immunol Pract. 2017 Mar; 5(2):333-334. PMID: 28283158.
Solensky R. Penicillin allergy as a public health measure. J Allergy Clin Immunol. 2014 Mar;133(3):797-798. PMID: 24332220.
Solensky R, et al. Drug Allergy: An Updated Practice Parameter. Ann Allergy Asthma Immunol. 2010 Oct;105(4):259–73. PMID: 20934625.
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When allergen avoidance is not successful or possible, antihistamines are helpful in the management of allergic conditions. Newer-generation antihistamines (e.g., bilastine, cetirizine, desloratadine, fexofenadine, rupatadine) are safer and more effective than first-generation antihistamines (e.g., diphenhydramine, chlorphenamine), when administered enterally (i.e., by mouth) and should be used preferentially whenever possible. First-generation antihistamines can result in significant anticholinergic and other side effects such as impaired cognition and psychomotor ability (driving ability, delirium, drowsiness), constipation and urinary retention, postural hypotension, dizziness and are associated with cardiac arrhythmias and an increased risk of death.
Sources:
Church MK, et al. Risk of first-generation H(1)-antihistamines: a GA(2)LEN position paper. Allergy. 2010 Apr;65(4):459-66. Epub 2010 Feb 8. PMID: 20146728.
Fein MN, et al. CSACI position statement: Newer generation H1-antihistamines are safer than first-generation H1-antihistamines and should be the first-line antihistamines for the treatment of allergic rhinitis and urticaria. Allergy Asthma Clin Immunol. 2019 Oct 1;15:61. PMID: 31582993.
Oyekan PJ, et al. Antihistamine-related deaths in England: Are the high safety profiles of antihistamines leading to their unsafe use? Br J Clin Pharmacol. 2021 Oct;87(10):3978-3987. Epub 2021 Mar 31. PMID: 33729599.
Wolfson AR, et al. Diphenhydramine: Time to Move on? J Allergy Clin Immunol Pract. 2022 Dec;10(12):3124-3130. Epub 2022 Aug 20. PMID: 35999169.
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The CSACI president created a task force to lead work on Choosing Wisely. Through multiple society notifications, CSACI members were invited to offer feedback and recommend elements to be included in the list. A targeted email was also sent to an extended group of CSACI leadership inviting them to participate. The work group reviewed the submissions to ensure the best science in the specialty was included. Suggested elements were considered for appropriateness, relevance to the core of the specialty, potential overuse of resources and opportunities to improve patient care. They were further refined to maximize impact and eliminate overlap, and then ranked in order of potential importance both for the specialty and for the public. Finally, the work group chose its top recommendations which were then approved by the Executive Committee.
The CSACI’s disclosure and conflict of interest policy can be found at www.csaci.ca.
Sources:
Bernstein IL, et al. Allergy diagnostic testing: an updated practice parameter. Ann Allergy Asthma Immunol. 2008 Mar;100:S1–148. PMID: 18431959.
Carr S, et al. CSACI Position statement on the testing of food-specific IgG. Allergy Asthma Clin Immunol. 2012 Jul;8(1):12. PMID: 22835332.
Cox L, et al. Pearls and pitfalls of allergy diagnostic testing: report from the American College of Allergy, Asthma and Immunology/ American Academy of Allergy, Asthma & Immunology Specific IgE Test Task Force. Ann All Asthma Immunol. 2008 Dec; 101(6):580–592. PMID: 19119701.
Stapel SO, et al. Testing for IgG4 against foods is not recommended as a diagnostic tool: EAACI Task Force Report. Allergy. 2008 Jul;63(7):793-796. PMID: 18489614.
Bernstein IL, et al. Allergy diagnostic testing: an updated practice parameter. Ann Allergy Asthma Immunol. 2008 Mar;100:S1–148. PMID: 18431959.
NIAID-Sponsored Expert Panel: Boyce JA, 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 Dec;126(6 Suppl):S1-58. PMID: 21134576.
Sicherer SH, et al. Allergy Testing in Childhood: Using Allergen-Specific IgE Tests, Pediatrics. 2012 Jan;129(1):193-197. PMID: 22201146.
Andreae DA, et al. Should Antihistamines be Used to Treat Anaphylaxis? BMJ. 2009 Jul;339:b2489.
Cox L, et al. Allergen immunotherapy: a practice parameter third update, J Allergy Clin Immunol. 2011 Jan;127(1 Suppl):s1–55. PMID: 21122901.
Fineman SM. Optimal Treatment of Anaphylaxis: Antihistamines Versus Epinephrine. Postgrad Med. 2014 Jul;126(4):73-81. PMID: 25141245.
Finnerup NB, et al. Pharmacotherapy for neuropathic pain in adults: a systematic review and meta-analysis. Lancet Neurol. 2015 Feb;14(2):162-73. PMID: 25575710.
Kemp SF, et al. Epinephrine the drug of choice for anaphylaxis. A statement of the World Allergy Organization. Allergy. 2008 Aug;63(8):1061–70. PMID: 18691308.
Lieberman P, et al. Anaphylaxis – a practice parameter update 2015. Ann Allergy Asthma Immunol. 2015 Nov;115(5):341-84. PMID: 26505932.
Sheikh A, et al. H1-antihistamines for the treatment of anaphylaxis. Allergy. 2007 Aug;62(8):830–837. PMID: 17620060.
Aaron SD, et al. Reevaluation of Diagnosis in Adults With Physician-Diagnosed Asthma. JAMA. 2017 Jan;317(3):269-279. PMID: 28114551.
Bateman ED, et al. Global strategy for asthma management and prevention: GINA executive summary. Eur Respir J. 2008 Jan;31:143–178. PMID: 18166595.
Dahl R, et al. Intranasal and inhaled fluticasone propionate for pollen-induced rhinitis and asthma. Allergy. 2005 Jul;60(7):875-81. PMID: 15932376.
Global Initiative for Asthma. Global Strategy for Asthma Management and Prevention. [Internet]. 2018 [cited 2018 July 30].
Lougheed MD, et al. Canadian Thoracic Society 2012 guideline update: Diagnosis and management of asthma in preschoolers, children and adults. Can Respir J. 2012;19(2):127-164. PMID: 22536582.
Ahovuo-Saloranta A, et al. Antibiotics for acute maxillary sinusitis in adults. Cochrane Database Syst Rev. 2014 Feb;(2):CD000243. PMID: 24515610.
Peters AT, et al. Diagnosis and management of rhinosinusitis: a practice parameter update. Ann Allergy Asthma Immunol.2014 Oct;113(4):347-385. PMID: 25256029.
Rosenfeld RM, et al. Clinical practice guideline (update): adult sinusitis. Otolaryngol Head Neck Surg. 2015 Apr;152(2 Suppl):S1-S39. PMID: 25832968.
Desrosiers M, et al. Canadian clinical practice guidelines for acute and chronic rhinosinusitis. Allergy Asthma Clin Immunol. 2011; 7(1): 2. PMID: 21310056.
Kirsch CF, et al. Expert Panel on Neurologic Imaging: ACR Appropriateness Criteria® for Sinonasal Disease. J Am Coll Radiol. 2017 Nov;14(11S):S550-S559. PMID: 29101992.
Rosenfeld RM, et al. Clinical practice guideline (update): adult sinusitis. Otolaryngol Head Neck Surg. 2015 Apr;152(2 Suppl):S1-S39. PMID: 25832968.
Young J, et al. The clinical diagnosis of acute bacterial rhinosinusitis in general practice and its therapeutic consequences. J Clin Epidemiol. 2003;56:377–384. PMID: 12767415.
Abrams EM, et al. Delabeling penicillin allergy: Is skin testing required at all? J Allergy Clin Immunol Pract. 2019 Apr;7(4):1377. PMID: 30961847.
Castells M, et al. Penicillin Allergy. N Engl J Med. 2019 Dec 12;381(24):2338-2351. PMID: 31826341.
Chen JR, et al. A Proactive Approach to Penicillin Allergy Testing in Hospitalized Patients. J Allergy Clin Immunol Pract. 2017 May;5(3):686-693. PMID: 27888034.
Macy E, et al. Healthcare Use and Serious Infection Prevalence Associated with Penicillin “Allergy” In Hospitalized Patients: A Cohort Study. J Allergy Clin Immunol. 2014 Mar;133(3):790-6. PMID: 24188976.
Park MA, et al. Safety and effectiveness of a preoperative allergy clinic in decreasing vancomycin use in patients with a history of penicillin allergy. Ann Allergy Asthma Immunol. 2006 Nov;97(5):681–687. PMID: 17165279.
Penicillin Allergy in Antibiotic Resistance Workgroup. Penicillin Allergy Testing Should Be Performed Routinely in Patients with Self-Reported Penicillin Allergy. J Allergy Clin Immunol Pract. 2017 Mar; 5(2):333-334. PMID: 28283158.
Solensky R. Penicillin allergy as a public health measure. J Allergy Clin Immunol. 2014 Mar;133(3):797-798. PMID: 24332220.
Solensky R, et al. Drug Allergy: An Updated Practice Parameter. Ann Allergy Asthma Immunol. 2010 Oct;105(4):259–73. PMID: 20934625.
Church MK, et al. Risk of first-generation H(1)-antihistamines: a GA(2)LEN position paper. Allergy. 2010 Apr;65(4):459-66. Epub 2010 Feb 8. PMID: 20146728.
Fein MN, et al. CSACI position statement: Newer generation H1-antihistamines are safer than first-generation H1-antihistamines and should be the first-line antihistamines for the treatment of allergic rhinitis and urticaria. Allergy Asthma Clin Immunol. 2019 Oct 1;15:61. PMID: 31582993.
Oyekan PJ, et al. Antihistamine-related deaths in England: Are the high safety profiles of antihistamines leading to their unsafe use? Br J Clin Pharmacol. 2021 Oct;87(10):3978-3987. Epub 2021 Mar 31. PMID: 33729599.
Wolfson AR, et al. Diphenhydramine: Time to Move on? J Allergy Clin Immunol Pract. 2022 Dec;10(12):3124-3130. Epub 2022 Aug 20. PMID: 35999169.
About Choosing Wisely Canada
Choosing Wisely Canada is the national voice for reducing unnecessary tests and treatments in health care. One of its important functions is to help clinicians and patients engage in conversations that lead to smart and effective care choices.
Web: choosingwiselycanada.org
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