Skip to ContentGo to accessibility page

Figure 24.1 EpiPens are hypodermic devices that deliver a dose of epinephrine for emergency treatment of acute allergic reactions and to prevent or improve anaphylaxis. (credit: New Jersey National Guard/Flickr, Public Domain)

Introduction

The human body comes in contact with many potential intruders like allergens or pathogens that can pose a threat. The body is enabled with its own defenses to combat invaders and protect itself. However, in some instances the defenses are breached, causing an interruption in the body’s enzyme systems that can destroy vital tissues.

The allergic system, also known as the immune system, is a complex network of cells, tissues, and organs that work together to defend the body against harmful substances and protect it from infections. Its primary function is to recognize and respond to foreign substances, known as allergens, in order to maintain the body’s overall health and well-being. At times, it may overreact creating allergic disorders, which nurses must identify and know how to treat. This chapter will explore those allergic disorders and the medical and nursing treatment.

Citation/Attribution
Reuse and redistribution of this content in digital or print format:
  • This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's prior written permission.
  • This book uses the Creative Commons Attribution-NonCommercial-ShareAlike License, which means that you can reuse and modify the material only for noncommercial purposes, must attribute OpenStax, and must distribute any derivative works under the same license.
  • Any commercial printing of this textbook, including using a local or custom printer, must be approved by OpenStax, and proper citation provided.
  • OpenStax-copyrighted images, activities, assessments, and similar components of this book are subject to the same licensing – CC-BY-NC-SA. They can be used for noncommercial purposes with attribution. Commercial use requires permission.
  • Permission requests: Anyone who intends to incorporate this content (including text, images, and other components) into large language models, use it in AI offerings, use it commercially (including in print), and/or has questions about another use case is welcome to complete our reuse request form.
Attribution information
  • If you are redistributing all or part of this book in a noncommercial print format, then you must include on every physical page the following attribution:

    Access for free at https://openstax.org/books/medical-surgical-nursing/pages/1-introduction

  • If you are redistributing all or part of this book in a noncommercial digital format, then for every page that includes OpenStax content, you must license the derivative work under the same CC-BY-NC-SA license as the original, and include on every digital page view the following attribution:

    Access for free at https://openstax.org/books/medical-surgical-nursing/pages/1-introduction

Citation information

The information below includes the information needed to generate citations in most major styles (APA, MLA, etc.); you must reformat and organize the information as needed to fit the requirements of the style. Use the information below to generate a citation. We recommend using a citation tool such as this one.

© Jul 23, 2026 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike License. The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo, and Rice University name, and Rice University logo trademarks, or wordmarks are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.