Chapter 23: Allergic Reaction
Topics
● Allergic Reactions
● Self-Administered Epinephrine
● EMT-Administered Epinephrine
Allergic Reactions
● The immune system naturally responds to foreign substances in body in order to get rid
of them
● An allergic reaction is an exaggerated immune response
● An allergen is a substance that causes an allergic reaction
● Anaphylaxis (anaphylactic shock) is a severe, life-threatening allergic reaction
○ Blood vessels dilate rapidly causing a drop in blood pressure (hypotension)
○ Cells leak-fluid into the interstitial space
○ Tissues swell, including the airways
● Causes of allergic reactions
○ Insects (bee, yellow jacket, wasp, and hornet sting)
○ Foods (nuts, eggs, and shellfish)
○ Plants (poison ivy, poison sumac, and poison oak)
○ Medications (penicillin)
○ Others (dust, chemicals, soap, and makeup)
● Latex allergy is of particular concern to EMS
○ Many patients have latex sensitivity
■ Patients who have had multiple surgeries are increasingly likely to have
this allergy
■ Wearing latex gloves while providing care can cause a reaction
○ Providers can also develop latex allergy from prolonged exposure
● An allergic reaction does not occur the first time a person encounters an allergen
○ On first exposure the immune system forms antibodies
○ On second exposure, the antibodies combine with the allergen
■ This combination causes release of histamines
■ These substances lead to a spectrum of reactions
● This spectrum of allergic reactions includes:
○ Dilation of blood vessels, which reduces the amount of blood returned to the
heart
○ Flushing of skin as blood vessels near the surface open up
○ Development of angioedema as fluid moves into tissues
○ Swelling around the vocal cords
○ Development of urticaria (hives) on the skin
○ Bronchoconstriction that decreases air movement in the lungs
○ Development of thick mucus in the lungs
● The exact cause of an allergic reaction is unpredictable
○ Severe reaction may be immediate but can be delayed 30 minutes or more
○ Mild allergic reaction can rapidly progress to anaphylaxis
, ● Closely monitor any patient exposed to a known allergen
● Signs and symptoms of allergic reaction:
○ Skin
■ Itching
■ Hives
■ Flushing (red skin)
■ Swelling of the face, neck, hands, feet, or tongue
■ Warm, tingling feeling in the face, mouth, chest, feet, or hands
○ Respiratory
■ Tightness in the throat or chest
■ Cough
■ Rapid, labored, and/or noisy breathing
■ Hoarseness, muffled voice, or loss of voice
■ Stridor
■ Wheezing (audible without stethoscope)
○ Cardiac
■ Increased heart rate
■ Decreased blood pressure
○ Generalized findings
■ Itchy, watery eyes
■ Headache
■ Runny nose
■ Sense of impending doom
○ Signs and symptoms of shock
■ Altered mental status
■ Flushed, dry skin or pale, cool, clammy skin
■ Nausea or vomiting
■ Changes in vital signs
● Increased pulse and respirations
● Decreased blood pressure
Allergic Reactions-Distinguishing Anaphylaxis from Mild Allergic Reaction
● Any of previous signs and symptoms can be associated with an allergic reaction
● To be anaphylaxis, the patient must have either respiratory distress or signs and
symptoms of shock
Allergic Reactions-Patient Assessment
● Perform a primary assessment and care for any immediate life threats (ABCs)
● During the secondary assessment, inquire about:
○ History of allergies
○ What was the patient exposed to
○ How the patient was exposed (route of exposure)
○ Signs and symptoms
○ Progression
Topics
● Allergic Reactions
● Self-Administered Epinephrine
● EMT-Administered Epinephrine
Allergic Reactions
● The immune system naturally responds to foreign substances in body in order to get rid
of them
● An allergic reaction is an exaggerated immune response
● An allergen is a substance that causes an allergic reaction
● Anaphylaxis (anaphylactic shock) is a severe, life-threatening allergic reaction
○ Blood vessels dilate rapidly causing a drop in blood pressure (hypotension)
○ Cells leak-fluid into the interstitial space
○ Tissues swell, including the airways
● Causes of allergic reactions
○ Insects (bee, yellow jacket, wasp, and hornet sting)
○ Foods (nuts, eggs, and shellfish)
○ Plants (poison ivy, poison sumac, and poison oak)
○ Medications (penicillin)
○ Others (dust, chemicals, soap, and makeup)
● Latex allergy is of particular concern to EMS
○ Many patients have latex sensitivity
■ Patients who have had multiple surgeries are increasingly likely to have
this allergy
■ Wearing latex gloves while providing care can cause a reaction
○ Providers can also develop latex allergy from prolonged exposure
● An allergic reaction does not occur the first time a person encounters an allergen
○ On first exposure the immune system forms antibodies
○ On second exposure, the antibodies combine with the allergen
■ This combination causes release of histamines
■ These substances lead to a spectrum of reactions
● This spectrum of allergic reactions includes:
○ Dilation of blood vessels, which reduces the amount of blood returned to the
heart
○ Flushing of skin as blood vessels near the surface open up
○ Development of angioedema as fluid moves into tissues
○ Swelling around the vocal cords
○ Development of urticaria (hives) on the skin
○ Bronchoconstriction that decreases air movement in the lungs
○ Development of thick mucus in the lungs
● The exact cause of an allergic reaction is unpredictable
○ Severe reaction may be immediate but can be delayed 30 minutes or more
○ Mild allergic reaction can rapidly progress to anaphylaxis
, ● Closely monitor any patient exposed to a known allergen
● Signs and symptoms of allergic reaction:
○ Skin
■ Itching
■ Hives
■ Flushing (red skin)
■ Swelling of the face, neck, hands, feet, or tongue
■ Warm, tingling feeling in the face, mouth, chest, feet, or hands
○ Respiratory
■ Tightness in the throat or chest
■ Cough
■ Rapid, labored, and/or noisy breathing
■ Hoarseness, muffled voice, or loss of voice
■ Stridor
■ Wheezing (audible without stethoscope)
○ Cardiac
■ Increased heart rate
■ Decreased blood pressure
○ Generalized findings
■ Itchy, watery eyes
■ Headache
■ Runny nose
■ Sense of impending doom
○ Signs and symptoms of shock
■ Altered mental status
■ Flushed, dry skin or pale, cool, clammy skin
■ Nausea or vomiting
■ Changes in vital signs
● Increased pulse and respirations
● Decreased blood pressure
Allergic Reactions-Distinguishing Anaphylaxis from Mild Allergic Reaction
● Any of previous signs and symptoms can be associated with an allergic reaction
● To be anaphylaxis, the patient must have either respiratory distress or signs and
symptoms of shock
Allergic Reactions-Patient Assessment
● Perform a primary assessment and care for any immediate life threats (ABCs)
● During the secondary assessment, inquire about:
○ History of allergies
○ What was the patient exposed to
○ How the patient was exposed (route of exposure)
○ Signs and symptoms
○ Progression
