Lyme rash reappearance probably signals new infection, study says

November 15, 2012 by Serena Gordon, Healthday Reporter
Lyme rash reappearance probably signals new infection, study says
It's even more likely when bull's-eye rash shows up on different part of body.

(HealthDay)—If you've had Lyme disease in the past and you develop another bull's-eye rash—the hallmark of Lyme disease—you probably have a new infection rather than a relapse of your initial infection, according to a small new study.

One implication of the study might be that since people don't suffer relapses from Lyme infection, it's not necessary to treat them with long-term antibiotics as a preventive measure.

For people whose symptoms do recur, it's especially likely that it's from a new infection if the rash shows up in a different site than the initial infection. It's also especially likely to be a new infection if it occurs during the prime tick season, which is from late spring through the summer, the study authors said.

"When people take the relatively short course of antibiotics that are ... recommended by the Infectious Diseases Society of America, the infection is likely to be cured," said the study's lead author, Dr. Robert Nadelman, a professor of medicine in the division of infectious diseases at New York Medical College in Valhalla, N.Y.

"But be aware that if you live, work or do recreation in an area with ticks, you can get tick bites again, and you can get Lyme again," he added. "If you see a tick on you, remove it promptly; take precautionary steps to try to avoid getting ticks on you."

Results of the study are published in the Nov. 15 issue of the New England Journal of Medicine.

The bull's-eye rash (called erythema migrans) that is usually the first clue that someone has been infected with generally disappears after treatment, according to study background information. But the rash comes back in about 15 percent of people who have had Lyme. Currently available tests can't differentiate between a new infection or a recurrent one. This can lead people to believe that they have a long-standing infection that requires long-term antibiotic therapy.

Ratner and his colleagues wanted to assess just how often a new bull's-eye rash is linked to a new infection or a recurrent one. To do this, they tested 22 skin or blood samples from 17 people who'd had a Lyme infection and then had a second, third or fourth episode of a new bull's-eye rash.

The researchers ran genetic tests on the samples to see if the strains of Borrelia burgdorferi were the same or different in each infection. B. burgdorferi is the bacterium transmitted by ticks to humans to cause Lyme disease.

None of the consecutive episodes of bull's-eye rashes was linked to the same strain of the bacteria.

"We found that in every single case, the subsequent infection was new," Nadelman said.

In addition, Nadelman said all of the new infections occurred during the tick-biting season—late spring to summer—and all of the rashes occurred at sites that were different from the initial infection. What these findings point to, he said, is a need for tick prevention.

One physician said the new findings lend more support to his current clinical practice.

"This study helps to solidify the confidence in what we're already doing," said Dr. Bruce Hirsch, an attending physician in at North Shore University Hospital, in Manhasset, N.Y. He said he already treats new rashes as new infections, and avoids prolonged antibiotic use in people with Lyme disease.

Hirsch added that for some people, it can take a while to get over a Lyme disease infection, even after the bacteria have been destroyed by antibiotics.

"An can sometimes take a toll on the body, requiring a significant recovery period, and it uses a tremendous amount of energy to get over some infections," he said.

Explore further: Deer tick bacteria DNA in joint fluid not reliable marker of active lyme arthritis

More information: Learn more about Lyme disease, including how to prevent it, from the U.S. Centers for Disease Control and Prevention.

Full Text (subscription or payment may be required)
Editorial (subscription or payment may be required)

Related Stories

Deer tick bacteria DNA in joint fluid not reliable marker of active lyme arthritis

May 17, 2011
New research shows that polymerase chain reaction (PCR) testing for Borrelia burgdorferi DNA—the spirochetal bacteria transmitted by deer ticks—in joint fluid may confirm the diagnosis of Lyme arthritis, but is ...

New test shows potential for detecting active cases of Lyme disease

May 24, 2012
George Mason University researchers can find out if a tick bite means Lyme disease well before the bite victim begins to show symptoms.

New tick-borne disease discovered

September 20, 2011
(Medical Xpress) -- Yale School of Public Health researchers in collaboration with Russian scientists have discovered a new tick-borne bacterium that might be causing disease in the United States and elsewhere. Their findings ...

Lyme disease bacteria take cover in lymph nodes

June 16, 2011
The bacteria that cause Lyme disease, one of the most important emerging diseases in the United States, appear to hide out in the lymph nodes, triggering a significant immune response, but one that is not strong enough to ...

Recommended for you

Google searches can be used to track dengue in underdeveloped countries

July 20, 2017
An analytical tool that combines Google search data with government-provided clinical data can quickly and accurately track dengue fever in less-developed countries, according to new research published in PLOS Computational ...

MRSA emerged years before methicillin was even discovered

July 19, 2017
Methicillin resistant Staphylococcus aureus (MRSA) emerged long before the introduction of the antibiotic methicillin into clinical practice, according to a study published in the open access journal Genome Biology. It was ...

New test distinguishes Zika from similar viral infections

July 18, 2017
A new test is the best-to-date in differentiating Zika virus infections from infections caused by similar viruses. The antibody-based assay, developed by researchers at UC Berkeley and Humabs BioMed, a private biotechnology ...

'Superbugs' study reveals complex picture of E. coli bloodstream infections

July 18, 2017
The first large-scale genetic study of Escherichia coli (E. coli) cultured from patients with bloodstream infections in England showed that drug resistant 'superbugs' are not always out-competing other strains. Research by ...

Ebola virus can persist in monkeys that survived disease, even after symptoms disappear

July 17, 2017
Ebola virus infection can be detected in rhesus monkeys that survive the disease and no longer show symptoms, according to research published by Army scientists in today's online edition of the journal Nature Microbiology. ...

Mountain gorillas have herpes virus similar to that found in humans

July 13, 2017
Scientists from the University of California, Davis, have detected a herpes virus in wild mountain gorillas that is very similar to the Epstein-Barr virus in humans, according to a study published today in the journal Scientific ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.