The difference between unfed and engorged female ticks.
Credit: Alexander Smith/University of Alberta
Lyme disease is an infection that is spread to humans through the bite of deer ticks carrying a bacterium, Borrelia burgdorferi. In 2012, there were nearly 25,000 confirmed cases of Lyme disease in the United States, according to the Centers for Disease Control and Prevention. The disease also affects people living in Asia and North Africa, and the World Health Organization estimates the total number of cases annually in Europe at 85,000.
The most common symptom of Lyme disease is a rash, medically called an erythema migrans lesion. Often known as a "bull's-eye" rash, the skin infection spreads gradually from the site of the tick bite in a widening circle. The rash typically forms within seven days after an individual is bitten and can persist for more than a month.
An erythema migrans lesion occurs in up to 90 percent of all Lyme patients, according to the American Lyme Disease Foundation. However, some of those who develop this skin infection don't realize they have a rash, said Dr. Gary Wormser, the chief of the Division of Infectious Diseases and head of the Lyme Disease Center at New York Medical College in Valhalla, New York.
"The Lyme rash is not particularly symptomatic; it's not particularly itchy or painful in most patients. If you don't look at your body that frequently, you may miss it," Wormser told Live Science.
The rash will usually clear up on its own in about four weeks, but the bacteria causing the infection still remain inside the body, Wormser said. Most Lyme patients who don't notice the rash and don't get treated right away will begin experiencing other symptoms as the bacteria spreads from the skin to the bloodstream.
Individuals may experience aches and pains accompanied by a fever, Wormser said. They may feel tired. Often these symptoms disappear on their own, leading individuals to think they are no longer sick. Eventually symptoms return, but it may be weeks or years after the initial bite. When they do return, the symptoms are typically more severe. In addition to the above symptoms, individuals may also notice tingling in the arms and legs. Arthritis may develop. Neurological problems can occur in late stages of the disease. These include memory loss and confusion.
Diagnosis & tests
Because the symptoms of Lyme disease overlap with those of other disorders, it is possible to receive a false diagnosis. Some patients with Lyme disease are misdiagnosed as having shingles, a painful skin inflammation caused by the same virus that causes chicken pox, according to Wormser.
Other patients may be misdiagnosed or treated for ordinary bacterial cellulitis, an infection of the skin caused by bacteria other than Borrelia burgdorferi.
To make a diagnosis of Lyme disease, a doctor will first take a history of the patient to determine what symptoms are present, if the person has any known tick bites and whether they were exposed to ticks, Wormser said.
A medical history is typically followed up with a full body exam, including a thorough examination of the skin. If an erythema migrans rash is found, no Lyme testing is needed to begin treatment, according to Wormser.
Early on in the Lyme infection, the immune system has not yet developed an antibody that can be detected with a blood test, which is why Wormser said he doesn't typically subject Lyme patients with the characteristic erythema migrans rash to diagnostic testing. For patients with the rash, Wormser said he begins treatment for Lyme immediately.
However, if a rash is absent, physicians will perform additional tests to confirm a diagnosis of Lyme disease.
An enzyme-linked immunosorbent assay test, also known as an ELISA test, is the standard blood test for Lyme disease. The test can determine whether the body's immune system has developed antibodies to react to any kind of Borrelia bacteria.
But because Borrelia bacteria are fairly common — they also cause sinus and urinary tract infections — antibodies for such bacteria may be present in the blood even if a person does not have Lyme disease, Wormser explained. For this reason, a positive ELISA test is followed up with another blood test called the Western blot. This test tells doctors what antigens are reacting with Borrelia antibodies, which helps them identify whether a person is infected specifically with the Borrelia burgdorferibacterium.
A test called polymerase chain reaction, or PCR, may be used for individuals who appear to have late-stage symptoms of the disease. Fluid from joints or the spine is analyzed for the presence of genetic material from the bacterium.
Treatments & medications
Patients who receive the proper treatment for Lyme disease typically recover quickly and completely, according to the Centers for Disease Control (CDC).
For the most part, antibiotics are effective if administered as soon as possible. Examples of common antibiotics used to treat Lyme disease include doxycycline and amoxicillin. Antibiotics are usually given for up to three weeks.
Individuals in later stages of the disease may require several courses of intravenous antibiotics, but there is the possibility that symptoms will persist.
The Mayo Clinic warns that individuals should avoid an alternative treatment called Bismacine. When used for Lyme disease or injected into the body, it can lead to bismuth poisoning and death.
Without treatment, or if treatment is unsuccessful, Lyme disease can cause serious complications. The bacterium that causes the disease initially infects the skin, but if the infection is left untreated, it can spread to other areas of the body, including the brain, where it can cause meningitis, according to Wormser.
Untreated Lyme can also lead to neurologic dysfunction, including paralysis of certain nerves, most commonly nerves in the face, bringing about a condition known as Bell's palsy. The disease can also have cardiovascular side effects such as abnormal heartbeat, fainting and even cardiac arrest and death, Wormser said.
However, the areas of the body most affected by Lyme disease are the joints, Wormser said.
"When you get another type of bacterial infection, you don't usually get arthritis, but one of the longer term complications of untreated Lyme is arthritis, or an actual swelling of a joint, not just pain in the joint," Wormser said.
Even after treatment with antibiotics, some Lyme patients may notice that they continue to have symptoms, such as fever and fatigue, according to Wormser. These symptoms are known collectively as post-treatment Lyme disease syndrome (PTLDS). Studies regarding the proper treatment of this syndrome and its causes are ongoing, and include various studies available through the National Institutes of Health.
One study, published in the Feb. 2013, edition of the International Journal of Infectious Diseases, found that 11 percent of the Lyme patients surveyed continued to experience symptoms of the disease six months after completing the recommended antibiotic treatment. Another study, published Oct. 5, 2012, in Open Neurology Journal, found that repeated treatment with antibiotics might be effective at treating PTLDS. However, a study published by Wormser and several colleagues on June 10, 2013, in the American Journal of Medicine found that retreatment of PTLDS patients with antibiotics was not effective.
PTLDS is sometimes referred to as chronic Lyme disease. However, chronic Lyme has also been used to describe the illnesses of people who have never been diagnosed with Lyme. For cases in which the patient has no history of Lyme, the nomenclature can be confusing. The cause of symptoms in these cases is not well understood and has been the subject of much controversy in recent years, Wormser said.
"The majority of patients that I see who have been treated for chronic Lyme don't show any evidence of ever having had Lyme. They just happen to have the same types of symptoms," Wormser said.
Prevention & tick removal
If you find a tick on your skin, you should remove it as soon as possible, Wormser said. He recommends using a pair of tweezers, and strongly advises against other methods of tick removal, including using chemicals on the skin or trying to burn the tick while it is still attached to the body.
"If you can get the tick off within 24 hours, you're not going to get Lyme disease," Wormser said. If you remove a tick and are not sure how long it's been attached to your body, you can also bring the tick with you to your doctor's appointment, he said. A doctor who specializes in Lyme should be able to measure the tick and tell you how long it's been attached to your skin and whether you're at risk of developing Lyme.
"You should do a tick check every 24 hours if you've been outside," Wormser said. "To do a good tick check, you really need a second person, because it's hard for you to see all the areas where the ticks could be biting you."
Wormser also recommends bathing within two hours of coming inside after being outdoors to prevent ticks from attaching to your skin. Wearing insect repellant on exposed skin and covering up as much as possible when spending time outdoors can also limit your exposure to Lyme, he said. If you do spend a lot of time outside, try to avoid walking through tall grass, as ticks tend to live in such areas.
This article is for informational purposes only, and is not meant to offer medical advice.
- It's Tick Time: Mayo Clinic Expert Offers Tips for Avoiding, Spotting Tick-Borne Diseases
- CDC: Lyme Disease Frequently Asked Questions (FAQ)
- National Library of Medicine: Tick Bites