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Expanding red rash after a tick bite

The rash is a flat, round patch that is usually about 2in across but can be much larger. The rash will gradually increase in size over a few days. As it does, the center of the patch where the tick was attached may become lighter in color, while the outer edge stays bright red. This makes the rash look like a bull's-eye.

One cause of an expanding red rash is Lyme disease.

The rash usually develops within 1 to 4 weeks after a tick bite. The average length of time before the rash appears is 10 days.

Author Jan Nissl, RN, BS
Editor Susan Van Houten, RN, BSN, MBA
Associate Editor Tracy Landauer
Primary Medical Reviewer William M. Green, MD - Emergency Medicine
Specialist Medical Reviewer H. Michael O'Connor, MD - Emergency Medicine
Last Updated January 17, 2008

WebMD Medical Reference from Healthwise

Last Updated: January 17, 2008
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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