Acute allergic reaction: Difference between revisions
(Diphenhydramine and famotidine are antagonists at the H receptor) |
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==Management== | ==Management== | ||
#[[H1 | #[[H1 antagonist]]: [[Diphenhydramine]] 50mg IV/IM/PO | ||
#[[H2 | #[[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 | ||
Revision as of 01:50, 1 November 2015
Background
- Similar to Anaphylaxis but does not meet all the requirements (i.e. just skin manifestations)
- Type I hypersensitivity reaction
Clinical Features
- Presentation can be delayed
Differential Diagnosis
Acute allergic reaction
- Allergic reaction/urticaria
- Anaphylaxis
- Angioedema
- Anxiety attack
- Asthma exacerbation
- Carcinoid syndrome
- Cold urticaria
- Contrast induced allergic reaction
- Scombroid
- Shock
- Transfusion reaction
Diagnosis
- Clinical
- Rule out Anaphylaxis
- Difficult to differentiate from Angioedema
Management
- H1 antagonist: Diphenhydramine 50mg IV/IM/PO
- H2 antagonist: Famotidine 40mg OR ranitidine 150mg IV/IM/PO
- Improves urticaria but not angioedema at 2 hours[1]
- 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
- ↑ 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.