Chapter 21: Allergy and Anaphylaxis – Key Vocabulary

Immunology

The study of the body’s immune system and its responses to foreign substances.

Allergic Reaction

An exaggerated immune response to any substance, causing symptoms such as itching, redness, and swelling.

Anaphylaxis

A severe, life-threatening systemic allergic reaction involving multiple organ systems that can lead to shock and death.

Local Reaction

Allergic response confined to one area, typically presenting with localized itching, redness, or swelling.

Systemic Reaction

A body-wide allergic response that can affect the respiratory and cardiovascular systems; may progress to anaphylaxis.

Histamines

Chemicals released during an allergic reaction that cause vasodilation, itching, and swelling.

Leukotrienes

Inflammatory chemicals released by the immune system that contribute to bronchoconstriction and airway edema.

Urticaria (Hives)

Raised, itchy, blotchy skin lesions common in allergic reactions.

Angioedema

Localized swelling beneath the skin or mucosa, especially around the eyes and lips, seen in severe allergies.

Wheezing

High-pitched whistling breath sound caused by lower-airway bronchospasm, often present in anaphylaxis.

Stridor

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

Hypotension

Abnormally low blood pressure; in anaphylaxis, caused by widespread vasodilation and capillary leakage.

Capillary Permeability

The capacity of blood vessels to allow fluid to leak into tissues, contributing to swelling and hypotension during anaphylaxis.

Allergen

Any substance that can trigger an allergic reaction, such as foods, medications, plants, chemicals, or insect venom.

Envenomation

The process by which an insect (or other animal) injects venom into a victim, potentially triggering an allergic reaction.

Epinephrine

A sympathomimetic hormone that reverses vasodilation, improves cardiac output, and relieves bronchospasm in anaphylaxis.

Sympathomimetic

Describes a drug that mimics the body’s sympathetic (fight-or-flight) response, such as epinephrine.

EpiPen

A pre-loaded auto-injector device that delivers a single dose of epinephrine (0.3 mg adult, 0.15 mg child).

Auto-Injector

Spring-loaded syringe designed for quick self-administration of medications like epinephrine.

Hypersensitivity Disorder

A condition in which the immune system overreacts to a stimulus, causing allergy-related illness.

ABCs

Assessment priorities of Airway, Breathing, and Circulation, critical in managing allergic emergencies.

SAMPLE History

Mnemonic for assessing Signs/Symptoms, Allergies, Medications, Past history, Last oral intake, Events leading to illness.

OPQRST

Pain assessment mnemonic: Onset, Provocation, Quality, Radiation, Severity, Time.

Medical Identification Tag

Bracelet or necklace indicating a patient’s medical conditions or severe allergies.

Index of Suspicion

The degree of clinical concern that a particular condition exists; should remain high for anaphylaxis.

Anaphylactic Shock

A severe form of shock caused by systemic vasodilation and airway compromise during anaphylaxis.

Insect Stinger

Barbed spine from insects like honeybees that can continue to inject venom if not removed.

Five Categories of Allergens

Food, medications, plants, chemicals (e.g., latex), and insect bites/stings.

Rapid Swelling

Quick onset edema of airway or tissues, a hallmark of severe allergic reactions.

Hypoperfusion

Inadequate blood flow to tissues; a sign of shock that may accompany anaphylaxis.

High-Flow Oxygen

Supplemental oxygen delivered at 10–15 L/min via nonrebreather mask, used in allergic emergencies with respiratory distress.

Positive-Pressure Ventilation

Assisted breathing technique for patients unable to ventilate adequately due to airway swelling.

Skill Drill 21-1

Procedure detailing the correct use of an EpiPen