Guideline sources The following summarized guidelines for the evaluation and management of acute urticaria are prepared by our editorial team based on guidelines from the Asia Pacific Association of Allergy, Asthma and Clinical Immunology (APAAACI/GA LEN/EDF/EAACI 2022), the Australasian College of Dermatologists (ACD 2021), the American Association of Family Physicians (AAFP 2017), and the American Academy of Allergy, Asthma & Immunology (AAAAI/ACAAI 2014). 1 2 3 4 Guidelines 1. Screening and diagnosis Pathophysiology: Recognize that acute urticaria and angioedema are often but not always related to mast cell and basophil activation from multiple triggers, which include IgE- and non-IgE-mediated mechanisms. B Recognize that acute urticaria and angioedema are more frequently associated with identifiable conditions. B Differential diagnosis: https://web.pathway.md/diseases/recV8S4OclNSBlh2R 1/3 6/23/23, 2:07 AM Acute urticaria Pathway As per AAFP 2017 guidelines, exclude underlying anaphylaxis in patients presenting with acute urticaria. B As per AAAAI 2014 guidelines: Differentiate acute urticaria and angioedema from chronic urticaria and angioedema based on the duration of illness. B Differentiate acute urticaria and angioedema from anaphylaxis. B 2. Classification and risk stratification Classification: classify urticaria based on its duration: acute ( 6 weeks) or chronic (> 6 weeks). A 3. Diagnostic investigations Initial evaluation: As per EAACI 2022 guidelines, do not obtain any routine diagnostic evaluation in patients with acute spontaneous urticaria. D As per ACD 2021 guidelines, do not obtain any routine investigations for underlying causes in patients with acute urticaria. D Show 2 more As per AAFP 2017 guidelines, do not obtain an extensive laboratory workup for urticaria. Consider obtaining additional testing if the presentation suggests underlying causes requiring confirmation. D 4. Diagnostic procedures Skin biopsy: consider performing skin biopsy in rare circumstances to differentiate acute urticaria and angioedema from other inflammatory disorders. C 5. Medical management Antihistamines: As per AAFP 2017 guidelines, administer second-generation H1RAs as first-line symptomatic therapy for urticaria. A Show 2 more As per AAAAI 2014 guidelines, administer antihistamines as first-line therapy in patients with acute urticaria and angioedema. B Corticosteroids: https://web.pathway.md/diseases/recV8S4OclNSBlh2R 2/3 6/23/23, 2:07 AM Acute urticaria Pathway As per AAFP 2017 guidelines, consider administering a short course of systemic corticosteroids to help control severe cases of urticaria. C As per AAAAI 2014 guidelines: Consider administering oral corticosteroids in patients with severe acute urticaria and angioedema. C Consider administering a short course of oral corticosteroids in patients with poor response to antihistamines, while attempting to eliminate suspected triggers and develop an effective treatment plan. C Corticosteroids (ECAAI): consider administering a short course of rescue systemic corticosteroids in patients with an acute exacerbation of chronic urticaria. C Leukotriene antagonists: consider offering leukotriene receptor antagonists to control symptoms of chronic urticaria. C Epinephrine autoinjectors: prescribe epinephrine if the diagnosis of anaphylaxis has not been excluded. B 6. Nonpharmacologic interventions Avoidance of causative agents: elicit a detailed history of common causes of acute urticaria and angioedema, including medications and foods, and instruct on proper elimination if identified. B References 1. Jonathan A Bernstein, David M Lang, David A Khan et al. The diagnosis and management of acute and chronic urticaria: 2014 update. J Allergy Clin Immunol. 2014 May;133 5 1270 7. Open 2. Paul Schaefer. Acute and Chronic Urticaria: Evaluation and Treatment. Am Fam Physician. 2017 Jun 1;95 11 717 724. Open 3. Torsten Zuberbier, Amir Hamzah Abdul Latiff, Mohamed Abuzakouk et al. The international EAACI/GA LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria. Allergy. 2022 Mar;77 3 734 766. Open 4. Australasian College of Dermatologists. Choosing Wisely ACD recommendations. Choosing Wisely. 2021. Open https://web.pathway.md/diseases/recV8S4OclNSBlh2R 3/3