Standard Article


  1. Lars Å Hanson

Published Online: 23 SEP 2005

DOI: 10.1038/npg.els.0003853



How to Cite

Hanson, L. Å. 2005. Allergy. eLS. .

Author Information

  1. Göteborg University, Göteborg, Sweden

Publication History

  1. Published Online: 23 SEP 2005

This is not the most recent version of the article. View current version (15 FEB 2013)


Allergic diseases are defined as hypersensitivity reactions caused by the immune system reacting erroneously to external material to which it normally should not react. There are two types of allergic disease, of which the most common and complex are the atopic allergies such as asthma and hay fever. A smaller group of patients have contact dermatitis caused by delayed hypersensitivity reactions.


  • hay fever;
  • atopic;
  • food allergy;
  • anaphylactic shock;
  • contact dermatitis