Go Slow on Lab Tests for Tick Bite, Erythema


LAS VEGAS — Patients who present with localized erythema near the site of a tick bite should not necessarily be referred for laboratory tests, Dr. Jana Hercogova said at a dermatology seminar sponsored by Skin Disease Education Foundation.

In fact, a tick bite followed by a local skin reaction should simply be examined in 1 week and, if the redness persists, treated with antibiotics, said Dr. Hercogova of Charles University, Prague.

Dr. Hercogova said that physicians treating pregnant women should consider the gestational age when choosing treatment. In the first trimester, she advised using penicillin G 20 million U/day for 2 days, with oral antibiotics as an option for the following 2 weeks. If infection is suspected to have begun in the second or third trimester, she said she uses only oral antibiotics—mainly penicillin derivatives.

Physicians should also be familiar with macular and annular erythema migrans, she noted, adding that patients with morphea should also be tested for Borrelia infection. However, she cautioned, “we should treat the patient without [serologic] evidence if we see a clinically clear case.”

If tests are done and come back positive for Lyme disease, she recommended treating the patient with doxycycline or penicillin, depending on whether Ehrlichia coinfection is present.

SDEF and this news organization are wholly owned subsidiaries of Elsevier.

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