Ask the Chatbot Games & Quizzes ProCon History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture Money Videos
patch test
Table of Contents
Introduction References & Edit History Related Topics
Related Questions
Read Next
Macro Aedes aegypti Mosquito. Close up a Mosquito sucking human blood,
Why Do Mosquito Bites Itch?
Aspirin pills.
7 Drugs that Changed the World
Photo of the antacid Tums
How Do Antacids Work?
Blackboard inscribed with scientific formulas and calculations in physics and mathematics
The World Science Festival’s Pioneers in Science
People wearing surgical masks (also called face mask or medical masks or safety masks) walk through the city center of Milan, Italy on Feb. 23, 2020. Coronavirus disease COVID-19 pandemic
How Do Face Masks Control the Spread of Disease?
Discover
Close up of books. Stack of books, pile of books, literature, reading. Homepage 2010, arts and entertainment, history and society
12 Novels Considered the “Greatest Book Ever Written”
Santa Claus flying in his sleigh, christmas, reindeer
Was Santa Claus a Real Person?
A Factory Interior, watercolor, pen and gray ink, graphite, and white goache on wove paper by unknown artist, c. 1871-91; in the Yale Center for British Art. Industrial Revolution England
Inventors and Inventions of the Industrial Revolution
New York NY/ USA- November 23, 2018 Hordes of shoppers throng the Macy's Herald Square flagship store in New York looking for bargains on the day after Thanksgiving, Black Friday.
Why Is It Called Black Friday?
Title: Senate Square, St. Petersburg, December 14, 1825: repression of the troop mutiny - watercolor by Carl Ivanovitch Kollman, 1825 depicts Decembrist uprising clashing with cavalry, with spectators watching. (new style December 26, 1825) Europe. Saint
8 of the Largest Empires in History
Iraqi Army Soldiers from the 9th Mechanized Division learning to operate and maintain M1A1 Abrams Main Battle Tanks at Besmaya Combat Training Center, Baghdad, Iraq, 2011. Military training. Iraq war. U.S. Army
8 Deadliest Wars of the 21st Century
Mayer Amschel Rothschild (1744-1855), founder of the house of Rothschild; lithograph by Friedrich Lieder, c. 1830.
Where Do Anti-Semitic Conspiracy Theories About the Rothschild Family Come From?

patch test

medicine
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Share
Share to social media
URL
https://www.britannica.com/science/patch-test
Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

External Websites
Written and fact-checked by
The Editors of Encyclopaedia Britannica
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.
The Editors of Encyclopaedia Britannica
Article History
Related Topics:
allergy
skin test
See all related content

patch test, controlled application of biological or chemical substances to the skin in order to detect if the subject has an allergic hypersensitivity to one of them. The test was originally developed to test new chemical compounds for their allergic potential on animals but has since become widely used to diagnose allergies in humans. Patch testing is usually done on the skin of the upper back or the outer arm. Small amounts of test substances diluted in a solvent such as water or petroleum jelly are applied to the skin under a patch of cloth or soft paper and an impermeable membrane. The patch is left in place for 48 hours, after which the skin reaction is examined and scored from 0 (no apparent reaction) to 4+, indicating severe blistering as well as angry redness of the exposed skin. Patch testing is an extremely accurate indicator of allergic sensitivity.