Sudden onset, usually in more than one body system, within minutes to a few hours of exposure to a trigger
Most common s/s are cutaneous (e.g., sudden onset of generalized urticaria, angioedema, flushing, pruritus) but 10 to 20% of patients have no skin findings
Treatment: mainly epinephrine (options for intranasal “Neffy” or intramuscular). See “Management of Shock” for additional details.
Labs: tryptase (elevation supports diagnosis)
Drug Allergies
High risk reaction: anaphylactic symptoms within 1-6 hours of medication within the last 5 years, SJS, TEN, serum sickness, mouth/eye ulcerations, DRESS
Low risk reaction: greater than 5 years since last reaction, urticaria only, GI symptoms only, remote childhood reaction with limited details, FH of drug allergy, known tolerance of drug since original reaction
Drug Challenge:
Diagnostic procedure to prove/disprove drug tolerance in patients who are thought unlikely to be truly allergic
Therapeutic procedure for known or highly suspected immediate hypersensitivity reactions when no acceptable alternative is available
Dose is incrementally increased over a short period of time until full dose is achieved and tolerated
Results in temporary tolerance to the medication
Contraindications: SJS, TEN, DRESS/DiHS, erythema multiforme, AGEP, serum sickness, serum sickness-like reactions, and nephritis, hepatitis and other organ specific reactions
Drug de-listing is important. “A recorded penicillin allergy was associated with a 14% increased risk of death. When allergy tested, 95% of adults with a recorded penicillin allergy are not allergic”
First line is nasal glucocorticoids (Fluticasone, Triamcinolone)
Daily nasal antihistamine (Azelastine)
Daily second-generation antihistamine (Loratadine, Fexofenadine, Cetirizine) Outpatient Medicine
Antihistamine eye drops (Olopatadine) for conjunctivitis
Combination therapy is often required
Review technique for nasal sprays: aim to outer corner of ipsilateral eye
Refractory to medical therapy: referral to Allergy for allergen immunotherapy
Food Allergies
Symptoms: pruritus, urticaria, flushing, swelling of the lips, face, or throat, nausea, vomiting, cramping, diarrhea, wheezing, lightheadedness, syncope or hypotension
Treatment:
Avoid the suspected food until further evaluation by an allergist
Prescribe epinephrine autoinjector PRN (educate patient on use)
Education: If the patient experiences prompt, complete, and durable response to one dose of epinephrine and has access to additional epinephrine autoinjectors, the patient does not have to present to the ER. Situations that would warrant EMS activation include severe anaphylaxis, symptoms that do not resolve promptly, completely or nearly completely, or symptoms that return or worsen
