Chapter 21 Allergy and Anaphylaxis – Key Vocabulary

This set of vocabulary flashcards covers essential terms, pathophysiology, assessment steps, common allergens, and emergency interventions related to Chapter 21, Allergy and Anaphylaxis, preparing students for recognition and management of allergic emergencies.

Allergic Reaction

An exaggerated immune response to a substance perceived by the body as foreign; ranges from mild, local signs (itching, redness) to severe systemic involvement.

Anaphylactic shock

A life-threatening systemic allergic reaction that is characterized as distributive shock with diaphoretic cool skin, hypotension, weak or irregular pulse, absent pulse and circulatory collapse

Hypersensitivity Disorder

A condition in which the immune system overreacts to stimuli (allergens), producing harmful effects such as allergies or anaphylaxis.

Immunology

The study of the body’s immune system, including its structure, function, and disorders such as allergic reactions.

Histamines

Chemicals released by the immune system during an allergic reaction that cause vasodilation, itching, and increased mucus production.

Leukotrienes

Inflammatory mediators released in allergic reactions that contribute to bronchoconstriction and airway edema.

Urticaria

Raised, red, itchy skin welts (hives) commonly seen in allergic reactions.

Angioedema

Swelling of the deeper layers of skin, often around the eyes, lips, or airway during anaphylaxis.

Wheezing

High-pitched whistling breath sound caused by lower-airway bronchospasm; frequent in anaphylaxis.

Stridor

Harsh, high-pitched inspiratory sound indicating upper-airway narrowing or obstruction.

Vasodilation

Widening of blood vessels; in anaphylaxis it contributes to hypotension and shock.

Capillary Permeability

Leakiness of capillary walls; increased during anaphylaxis, leading to swelling and hypotension.

Envenomation

Process of an insect injecting venom through a sting or bite, potentially triggering an allergic reaction.

Common Allergen: Food

Edibles such as shellfish or peanuts that frequently precipitate anaphylaxis; symptoms may be delayed and include GI upset.

Common Allergen: Medication

Drugs (e.g., antibiotics, NSAIDs) that can cause rapid and severe allergic reactions, especially when injected.

Common Allergen: Plants

Pollens or plant materials (ragweed, ryegrass) capable of producing rapid, sometimes severe, allergies.

Common Allergen: Chemicals

Substances like latex, soaps, or cosmetics that may provoke allergic reactions on contact.

Common Allergen: Insect Stings

Venom from bees, wasps, hornets, or fire ants; may cause localized pain or systemic anaphylaxis.

Epinephrine

A sympathomimetic hormone/drug that constricts blood vessels, relaxes bronchioles, and reverses anaphylaxis.

Sympathomimetic

A medication that mimics the body’s fight-or-flight (sympathetic) response; epinephrine is one example.

EpiPen Auto-Injector

Pre-loaded device that delivers a preset dose of epinephrine (0.3 mg adult, 0.15 mg child) for anaphylaxis.

Anaphylactic Shock

Severe form of shock caused by widespread vasodilation and fluid leakage during anaphylaxis, resulting in hypotension.

ABC Management

Prioritizing Airway, Breathing, and Circulation—critical when treating allergic reactions to prevent airway compromise and shock.

Primary Assessment

Initial evaluation focusing on life threats, including rapid airway and breathing checks in suspected anaphylaxis.

Secondary Assessment

Focused or head-to-toe exam to find additional signs of an allergic reaction after life threats are addressed.

SAMPLE History

Mnemonic (Signs/Symptoms, Allergies, Medications, Past history, Last oral intake, Events) used to gather patient history.

OPQRST

Pain-assessment mnemonic (Onset, Provocation, Quality, Region/Radiation, Severity, Time) applied during history taking.

Medical Identification Tag

Bracelet or necklace indicating a patient’s severe allergy, useful when the patient can’t communicate.

High-Flow Oxygen

Supplemental O₂ delivered at 10–15 L/min via nonrebreather mask to improve oxygenation in respiratory compromise.

Positive Pressure Ventilation

Forcing air into lungs with a BVM; may be required in severe anaphylaxis with inadequate breathing.

Stinger Removal

Technique of scraping a honeybee stinger sideways with a stiff object (e.g., credit card) to prevent more venom release.

Supportive Care

Monitoring, airway maintenance, oxygen, and positioning given to mild allergic patients not requiring epinephrine.

Epinephrine Contraindications (Geriatric)

Relative concerns such as severe hypertension, tachydysrhythmias, or coronary artery disease that may complicate epinephrine use in elderly patients.

Skill Drill 21-1

Training exercise that demonstrates proper EpiPen use, including site selection, activation, and post-administration care.

Pulse Oximetry

Non-invasive device measuring oxygen saturation; guides but does not replace clinical judgment in allergic emergencies.

Transport Decision

Determination to move the patient promptly, especially if anaphylaxis is suspected or symptoms are worsening.

Antigen

A substance that stimulates an immune response

Immune systems

The body’s defense mechanism against foreign substances that may invade the body

White blood cells recognize and destroy antigens

Carries out immune functions

sensitized, will react strong next time

After being exposed to antigens, the immune system becomes

Urticaria

Hives

High fowlers

Position for anaphylaxis