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Recurring Lyme Disease Rash Caused By Reinfection, Not Relapse
Originally published on Thu December 6, 2012 4:30 pm
In recent years, a disease spread by ticks has become more common across the country.
Lyme disease causes a skin rash, and in some cases, more serious symptoms. The rash usually goes away with antibiotics, but some people say they have other symptoms that persist for months or years.
Now a study published in the latest issue of The New England Journal of Medicine suggests those with a recurring rash don't have one long illness. Instead, they're getting new infections from fresh tick bites.
Researchers recently conducted an experiment in which they examined Lyme disease-causing bacteria in the blood of 17 patients suffering from a recurrence of the rash. Then they compared these bacteria to a sample taken from the same patients during an earlier flare-up of Lyme symptoms.
If Lyme disease actually were a chronic condition, you'd expect the two bacteria samples to be identical. But they weren't.
"These were different bacteria," says Dr. Robert Nadelman, an infectious disease specialist at New York Medical College. "One can infer from that that these are different infections, and therefore caused by different tick bites, as opposed to people who possibly could have had relapses of infections that weren't adequately treated."
For many people, Nadelman says, it's easy to get newly infected with Lyme disease — especially for those living in the Northeast.
"People still live in areas where there are deer ticks, or they work in areas where there are deer ticks, or they have recreation in areas where there are deer ticks," he says. "And the tick bites themselves are ... on body parts that you don't see very well, such as the buttocks or behind the knee."
Not every doctor agrees with the findings. Dr. Samuel Shor, a professor at George Washington University, says a study examining only 17 patients isn't large enough to draw any conclusions.
Still, whether or not Lyme disease is a chronic condition, in rare cases, it is a very serious condition.
Dr. Allen Steere, a rheumatologist at Massachusetts General Hospital who's studied Lyme disease for decades, says that without treatment, Lyme disease can lead to abnormalities in the heart and brain within weeks of an infection.
He says patients at risk of contracting Lyme disease will notice a bug bite surrounded by a red rash that expands slowly and eventually grows to the size of a plate or even larger. Steere says if patients see this and also feel stiff, achy or feverish, they should see a doctor immediately.
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In recent years, Lyme disease, spread by ticks, has become more common all over the country. It causes a skin rash and, in some cases, more serious symptoms. They usually go away with antibiotics, but some people have symptoms for months or years.
Well, now a new study in The New England Journal of Medicine suggests that people with chronic symptoms don't have one long illness; they have repeated infections, as NPR's Patti Neighmond explains.
PATTI NEIGHMOND, BYLINE: To figure out whether people were suffering a relapse, researchers analyzed the genetics of the bacteria that causes Lyme disease. They looked at blood cultures in patients or biopsies of the patient's skin rash. Dr. Robert Nadelman headed the study.
DR. ROBERT NADELMAN: We went back and we looked at the specimens that we had saved all these years in the freezer to compare the characteristics of the bacterial strains from each episode that the patient had.
NEIGHMOND: Nadelman's an infectious disease specialist at New York Medical College. He figured if patients were suffering a relapse, then the bacteria infecting them would be the same every time symptoms reappeared. But that's not what he found in the study, which looked at 17 patients.
NADELMAN: These were different bacteria, which one can infer from that that these are different infections, and therefore caused by different tick bites, as opposed to people who possibly could have had relapses of infections that weren't adequately treated.
NEIGHMOND: Treatment is typically a course of two to four weeks of antibiotics. George Washington University professor, Dr. Samuel Shor, says that for some people, treatment doesn't work. Signs of the infection may go away in the blood but symptoms persist.
DR. SAMUEL SHOR: There are a substantial number of people who have sustained symptoms after three to four weeks of antibiotics who either get better or don't improve and go on to have more chronic symptoms.
NEIGHMOND: Shor says the new study isn't large enough to say conclusively that people with chronic Lyme disease are simply getting reinfected. But Dr. Nadelman says for many people, it's easy to get reinfected, particularly in the humid Northeast where deer ticks are flourishing.
NADELMAN: And the reason for this is because people still live in areas where there are deer ticks, or they work in areas where there are deer ticks, or they have recreation in areas where there are deer ticks. And the tick bites themselves are usually not appreciated by patients. They're not painful. They don't itch very much. And often, they're on body parts that you don't see very well, such as the buttocks or behind the knee.
NEIGHMOND: And after a bite from an infected tick, people typically get a set of classic symptoms. Dr. Allen Steere is with Massachusetts General Hospital.
DR. ALLEN STEERE: The most common initial sign of the infection is this initial skin lesion and its slowly expanding redness. If a person sees that, and particularly if they feel sick with it - fever, headache, neck stiffness, joint aches - they should go to the doctor.
NEIGHMOND: Steere has studied Lyme disease for more than three decades. He says antibiotic therapy is critical in order to rid the body of the disease.
STEERE: Without antibiotic therapy, the organism will often disseminates to other sites in the body. And within several weeks, it may cause neurologic involvement or cardiac abnormalities. And within months, it may cause arthritis.
NEIGHMOND: Steere says the new study adds weight to evidence that antibiotics cure patients and that people who suffer recurrent rashes are actually getting infected by the bite of another tick. Patti Neighmond, NPR News.
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