Acute allergic reaction: Difference between revisions

(Text replacement - " ==" to "==")
(3 intermediate revisions by 3 users not shown)
Line 10: Line 10:
{{Acute Allergic DDX}}
{{Acute Allergic DDX}}


==Diagnosis==
==Evaluation==
*Clinical
*Clinical
**Rule out [[Anaphylaxis]]
**Rule out [[Anaphylaxis]]
Line 17: Line 17:
==Management==
==Management==
#[[H1 antagonist]]: [[Diphenhydramine]] 50mg IV/IM/PO
#[[H1 antagonist]]: [[Diphenhydramine]] 50mg IV/IM/PO
#*H1 antagonists with low sedating activity, such as fexofenadine, loratadine, cetirizine, are preferred over diphenhydramine and hydroxyzine when appropriate<ref>[Guideline] Zuberbier T, Asero R, Bindslev-Jensen C, Walter Canonica G, Church MK, Giménez-Arnau AM, et al. EAACI/GA(2)LEN/EDF/WAO guideline: management of urticaria. Allergy. 2009 Oct. 64(10):1427-43</ref>
#*H1 antagonists with low sedating activity, such as fexofenadine, loratadine, cetirizine, are preferred over [[diphenhydramine]] and hydroxyzine when appropriate<ref>[Guideline] Zuberbier T, Asero R, Bindslev-Jensen C, Walter Canonica G, Church MK, Giménez-Arnau AM, et al. EAACI/GA(2)LEN/EDF/WAO guideline: management of urticaria. Allergy. 2009 Oct. 64(10):1427-43</ref>
#[[H2 antagonist]]: [[Famotidine]] 40mg OR [[ranitidine]] 150mg IV/IM/PO
#[[H2 antagonist]]: [[Famotidine]] 40mg '''OR''' [[ranitidine]] 150mg IV/IM/PO
#*Improves urticaria but not angioedema at 2 hours<ref>Lin, RY et al. Improved Outcomes in Patients With Acute  Allergic Syndromes Who Are Treated With  Combined H1 and H2 Antagonists. Annals of Emergency Medicine. 36:5 NOVEMBER 2000.</ref>
#*Improves urticaria but not angioedema at 2 hours<ref>Lin, RY et al. Improved Outcomes in Patients With Acute  Allergic Syndromes Who Are Treated With  Combined H1 and H2 Antagonists. Annals of Emergency Medicine. 36:5 NOVEMBER 2000.</ref>
#Consider [[corticosteroid]]: [[methylprednisolone]] 125mg IV/IM OR [[prednisone]] 60mg PO
#Consider [[corticosteroid]]: [[methylprednisolone]] 125mg IV/IM '''OR''' [[prednisone]] 60mg PO
#*Continue steroid burst if outpatient (40mg [[prednisone]] PO x 5 days)
#*Continue steroid burst if outpatient (40mg [[prednisone]] PO x 5 days)


Line 28: Line 28:
==See Also==
==See Also==
*[[Anaphylaxis]]
*[[Anaphylaxis]]
*[[Chronic urticaria]]


==References==
==References==

Revision as of 15:52, 17 August 2019

Background

Clinical Features

Raised urticaria
  • Presentation can be delayed

Differential Diagnosis

Acute allergic reaction

Evaluation

Management

  1. H1 antagonist: Diphenhydramine 50mg IV/IM/PO
    • H1 antagonists with low sedating activity, such as fexofenadine, loratadine, cetirizine, are preferred over diphenhydramine and hydroxyzine when appropriate[1]
  2. H2 antagonist: Famotidine 40mg OR ranitidine 150mg IV/IM/PO
    • Improves urticaria but not angioedema at 2 hours[2]
  3. Consider corticosteroid: methylprednisolone 125mg IV/IM OR prednisone 60mg PO
    • Continue steroid burst if outpatient (40mg prednisone PO x 5 days)

Disposition

  • Consider brief observation in the ED for improvement of symptoms

See Also

References

  1. [Guideline] Zuberbier T, Asero R, Bindslev-Jensen C, Walter Canonica G, Church MK, Giménez-Arnau AM, et al. EAACI/GA(2)LEN/EDF/WAO guideline: management of urticaria. Allergy. 2009 Oct. 64(10):1427-43
  2. Lin, RY et al. Improved Outcomes in Patients With Acute Allergic Syndromes Who Are Treated With Combined H1 and H2 Antagonists. Annals of Emergency Medicine. 36:5 NOVEMBER 2000.