I was bitten by a deer tick behind my right ear lobe yesterday. The sight of the bite is a dark red circle that is painful. I have a headache today.

The red circle you are seeing may be a reaction to the bite itself.

As you know, Lyme disease can occur following a bite by a deer tick. The tick has to be attached to the body for quite a while to cause an illness, about one to two days. The typical rash of Lyme disease, called erythema migrans, starts sometime after the third day and can become quite large. The early symptoms often include feeling tired, feverish and achy. These symptoms are, of course, common to a lot of infections. There are no tests that are likely to be useful at this stage. [It takes several weeks for the body produces antibodies to the Lyme disease organism, which can then be measured in the blood.]

The major problems with Lyme disease occur weeks to months after a tick bite. Lyme disease is not too common, about 15,000 cases a year in the whole country.

Unfortunately, we are not able to diagnose Lyme disease on the web site. The diagnosis requires a careful exam by a physician. Even then, it may not be an easy diagnosis especially at such an early point.

I hope you have already seen your physician for an examination of the bite mark. Depending on your specific situation, including how long the tick was attached, physicians will sometimes recommend a dose of antibiotics that can prevent Lyme disease. This single dose of antibiotic treatment works best if given within 72 hours of the bite.

Thank you for your question. I hope you will let us know what happens.

Dr. Joshua Rassen

-- Joshua Rassen, MD, is a board-certified internist and geriatrician in northern California. He has a private practice in geriatrics and internal medicine and is the Chief of the Division of General Internal Medicine at California Pacific Medical Center.

First published March 29, 2005
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