Healthopedia.com - Your Health
Encyclopedia

Set Homepage Email Page Favorites      

 
  Home
  Health Centers
  Medical Encyclopedia
  Drugs & Medications
  Diseases & Conditions 
  Medical Symptoms
  Medical Tests & Exams
  Surgery & Procedures 
  Injuries & Wounds
  Diet & Nutrition
  Special Topics
  Pictures & Images      


Google
 
Web Healthopedia.com

You are here : Healthopedia.com > Medical Encyclopedia > Diseases and Conditions > Allergic Reactions
      Category : Health Centers > Allergies

Allergic Reactions

Alternate Names : Acquired Sensitivity Reaction, Induced Sensitivity Reaction

Overview, Causes, & Risk Factors | Symptoms & Signs | Diagnosis & Tests | Prevention & Expectations | Treatment & Monitoring | Attribution


An allergic reaction is an immune system response to exposure to a specific substance.

What is going on in the body?

Allergic reactions are fairly common. Most reactions happen soon after contact with an allergen. An allergen is a trigger that causes the reaction after touching a certain part of the body.

  • The blood may be exposed from an injection.
  • The blood or gut may be exposed from swallowing an allergen.
  • The lungs may be exposed from inhaling the allergen.
  • The skin may be directly exposed to an allergen.
  • Usually these reactions are mild and can be treated at home with simple methods. However, some people have a sudden, life-threatening allergic reaction within minutes, called anaphylaxis. Anaphylaxis can progress rapidly and result in shock and even death if medical help is not obtained quickly.

    Usually, the first exposure produces only a very mild reaction or no reaction at all. For some people, repeated exposure may lead to more serious reactions. Even a small amount of a trigger can lead to a serious reaction in some people. Allergic reactions can affect small areas or the entire body. Most reactions occur within seconds or minutes of exposure. However, some reactions can occur days or weeks after exposure.

    What are the causes and risks of the condition?

    There are few things that do not cause an allergic reaction in some people. However, most people never have an allergic reaction. Those with a family history of allergies are more likely to develop them. People with asthma, hay fever, or a skin condition known as eczema are more likely to develop allergies.

    Following are some of the common triggers:

  • bee stings
  • foods such as peanuts and shrimp, which can trigger a food allergy
  • medicines
  • metals
  • mold
  • pets with feathers or fur
  • pollens or plants
  • synthetic materials
  • tiny organisms such as bacteria

  •    

    Next section

       

    Allergic Reactions: Symptoms & Signs

    Author: James Broomfield, MD
    Reviewer: William M. Boggs, MD
    Date Reviewed: 08/21/01









    Content provided by The Patient Marketing Group, Inc.

    Copyright © 2006 Healthopedia.com All Rights reserved.
    About Us | Help/FAQ | Privacy Policy | Editorial Policy | Advertising Policy | Accessibility | Terms of Use
    Contact Us | Link to Us

    HONcode accreditation seal.

    We comply with the HONcode standard for health trust worthy information: verify here.


    The information provided herein is intended for your general knowledge only and is not a substitute for medical advice or treatment for specific medical conditions. The information should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call your local emergency number for all medical emergencies. Use of this online service is subject to the disclaimer and the terms and conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites.
    Page Last Updated: 30th May, 2006