Allergic Reactions

Allergic reaction vs anaphylaxis

Allergic reaction: Exaggerated immune response to an allergen

Anaphylaxis: Life threatening allergic reaction causing respiratory distress and / or signs of shock

Allergen

Substance that triggers an allergic reaction

Insects (Bees / wasps / hornets)

Food (Nuts, eggs, milk, shellfish)

Farmaceuticals (Penicillin)

Latex

Why doesnt an allergic reaction happen the first time someone is exposed

1st exposure: Immune system makes antibodies

2nd exposure: Antibodies bind the allergen → Histamine released

Three major effects histamines cause

(Think opposite of epinephrine)

Vasodilation → Hypotension

Increased capillary permeability (Leaky) → Swelling

Bronchoconstriction → Wheezing & reduced airflow

Three major effects epinephrine has

(Think opposite of histamines)

Vasoconstricts blood vessels

Decreased capillary permeability (Stops leaking)

Bronchodilates

Findings indicative of respiratory distress in anaphylaxis

SWAT

Stridor

Wheezing

Airway tightness

Talking changes

Stridor, wheezing, tight throat / chest, hoarse / muffed voice, rapid / labored breathing

Signs suggesting anaphylactic shock

AMS, hypotension, tachycardia, cool, pale, clammy skin, nausea / vomiting

EMT Treatment sequence for anaphylaxis

ABCs

High concentration oxygen

Epinephrine

Document time

Transport

Reassess every 2 minutes

Angiodema

Swelling beneath the skin caused by leaking capillaries, commonly affecting the lips, tongue, face, and airway

Urticaria

Raised, itchy welts on the skin (Hives)

Urticaria is superficial, angioedema is deeper

Common skin findings in allergic reactions

Itching, hives, flushing, swelling of face, hands, neck, or feet

Generalized findings of allergic reactions

Itchy / watery eyes, runny nose, headache, sense of impending doom

Common side effects of epinephrine

Tachycardia, hypertension, pallor, anxiety / excitability, chest pain, headache, nausea / vomiting