If allergic features, antihistamine daily for several days
If steroid prescribed, complete short course as directed
Avoidance plan
Avoid ACE inhibitors permanently if suspected cause
Avoid known triggers and NSAIDs if prior reactions
Epinephrine auto-injector plan when indicated
Carry at all times if anaphylaxis risk
Use immediately for trouble breathing, throat tightness, fainting, or widespread hives
Return to ED now for red flags
Voice change or hoarseness
Trouble breathing or wheeze
Trouble swallowing or drooling
Tongue swelling or worsening facial swelling
Dizziness, fainting, or low blood pressure symptoms
Follow-up
Primary care within 1 to 3 days
Allergy and immunology referral for recurrent episodes or suspected hereditary disease
References
Guidelines and evidence
Guideline sources
ACEP clinical policy and evidence levels for anaphylaxis and allergic emergencies
Epinephrine as first line for anaphylaxis (ACEP Level B to C depending on endpoint and setting)
Antihistamines and steroids as adjuncts only (ACEP Level C)
World Allergy Organization anaphylaxis guidance
IM epinephrine first line
Observation for biphasic reaction based on severity
AAAAI and ACAAI practice parameters for anaphylaxis and angioedema
Differentiation of histamine vs bradykinin mediated disease
Role of C4 and C1 inhibitor testing for hereditary disease
HAE international consensus guidance
C1 inhibitor concentrate and icatibant for acute attacks
Avoidance of ACE inhibitors in hereditary disease
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.