The Terror Behind the Bite: Lyme Disease

Almost all people know what a tick is. Some even know that ticks can transmit lyme disease. But very few people know and understand the dangers of this dreadful bacterial infection.

Blacklegged ticks are quite small and can be mistaken for a freckle. From left to right: The blacklegged tick larva, nymph, adult female and adult male. When the blacklegged tick is in its nymph stage, the risk of transmission of Lyme disease is the greatest. Nymphs are tiny (less than 2 mm) and are difficult to see - Credit: Fairfax County via Flickr

From left to right: The blacklegged tick larva, nymph, adult female and adult male. When the blacklegged tick is in its nymph stage, the risk of transmission of Lyme disease is the greatest. Nymphs are tiny (less than 2 mm) and are difficult to see – Credit: Fairfax County via Flickr

Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted to humans through the bite of infected blacklegged ticks. If left untreated, infection can spread to joints, the heart, and the nervous system. Lyme disease is diagnosed based on symptoms, physical findings (e.g., rash), and the possibility of exposure to infected ticks. Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics. 

Shows the rash often associated with a tick-bite-induced lyme disease - Credit: monkeypuzzle via Flickr

Shows the rash often associated with tick-bite-induced lyme disease – Credit: monkeypuzzle via Flickr

Did you know? In 2011, 96% of Lyme disease cases were reported from 13 states: Connecticut, Delaware, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Vermont, Virginia, and Wisconsin.

Lyme disease risk map - Credit: February issue of the American Journal of Tropical Medicine and Hygiene

Lyme disease risk map – Credit: February issue of the American Journal of Tropical Medicine and Hygiene

Prevention

Below are some tips to help prevent your exposure to ticks and the threat of Lyme disease:

  • Avoid wooded and bushy areas with high grass and leaf litter.
  • Walk in the center of trails.
  • Use repellents that contain 20% or more DEET (N, N-diethyl-m-toluamide) on the exposed skin for protection that lasts up to several hours. Always follow product instructions. Parents should apply this product to their children, avoiding hands, eyes, and mouth.
  • Use products that contain permethrin on clothing. Treat clothing and gear, such as boots, pants, socks and tents. It remains protective through several washings. Pre-treated clothing is available and remains protective for up to 70 washings.
  • Bathe or shower as soon as possible after coming indoors (preferably within two hours) to wash off and more easily find ticks that are crawling on you.
  • Conduct a full-body tick check using a hand-held or full-length mirror to view all parts of your body upon return from tick-infested areas. Parents should check their children for ticks under the arms, in and around the ears, inside the belly button, behind the knees, between the legs, around the waist, and especially in their hair.
  • Examine gear and pets. Ticks can ride into the home on clothing and pets, then attach to a person later, so carefully examine pets, coats, and day packs. Tumble clothes in a dryer on high heat for an hour to kill remaining ticks.
Credit: d_vdm via Flickr

Credit: d_vdm via Flickr

Signs & Symptoms

If you had a tick bite, live in an area known for Lyme disease or have recently traveled to an area where it occurs, and observe any of these symptoms, you should seek medical attention!

Early localized stage (3-30 days after tick bite):

  • Red, expanding rash called erythema migrans (EM)
    • Rash occurs in approximately 70-80% of infected persons1 and begins at the site of a tick bite after a delay of 3-30 days (average is about 7 days).
    • Rash gradually expands over a period of several days, and can reach up to 12 inches (30 cm) across. Parts of the rash may clear as it enlarges, resulting in a “bull’s-eye” appearance.
    • Rash usually feels warm to the touch but is rarely itchy or painful.
    • EM lesions may appear on any area of the body.
  • Fatigue, chills, fever, headache, muscle and joint aches, and swollen lymph nodes

Some people may get these general symptoms in addition to an EM rash, but in others, these general symptoms may be the only evidence of infection. Some people may also get a small bump or redness at the site of a tick bite that goes away in 1-2 days, like a mosquito bite. This is not a sign that you have Lyme disease. However, ticks can spread other organisms that may cause a different type of rash. For example, Southern Tick-associated Rash Illness (STARI) causes a rash with a very similar appearance.

Erythema migrans (EM) or "bull's-eye" rash - Credit: CDC

Erythema migrans (EM) or “bull’s-eye” rash – Credit: CDC

Early disseminated stage (days to weeks after tick bite):

  • Additional EM lesions in other areas of the body
  • Facial or Bell’s palsy (loss of muscle tone on one or both sides of the face)
  • Severe headaches and neck stiffness due to meningitis (inflammation of the spinal cord)
  • Pain and swelling in the large joints (such as knees)
  • Shooting pains that may interfere with sleep
  • Heart palpitations and dizziness due to changes in heartbeat
Bell's (facial) palsy - Credit: CDC

Bell’s (facial) palsy – Credit: CDC

Late disseminated stage (months to years after tick bite):

  • Approximately 60% of patients with untreated infection may begin to have intermittent bouts of arthritis, with severe joint pain and swelling. Large joints are most often affected, particularly the knees. Arthritis caused by Lyme disease manifests differently than other causes of arthritis and must be distinguished from arthralgias (pain, but not swelling, in joints).
  • Up to 5% of untreated patients may develop chronic neurological complaints months to years after infection. These include shooting pains, numbness or tingling in the hands or feet, and problems with short-term memory.
Arthritis - Credit: CDC

Arthritis – Credit: CDC

Treatment

Patients treated with appropriate antibiotics in the early stages of Lyme disease usually recover rapidly and completely. Antibiotics commonly used for oral treatment include:

  • Doxycycline
  • Amoxicillin
  • Cefuroxime Axetil

Patients with certain neurological or cardiac forms of illness may require intravenous treatment with drugs such as:

  • Ceftriaxone
  • Penicillin

Approximately 10-20% of patients (particularly those who were diagnosed later), following appropriate antibiotic treatment, may have persistent or recurrent symptoms and are considered to have Post-treatment Lyme disease syndrome (PTLDS). The National Institutes of Health (NIH) has funded several studies on the treatment of Lyme disease which show that most patients recover when treated with a few weeks of antibiotics taken by mouth.

Credit: Lennart Tange via Flickr

Credit: Lennart Tange via Flickr

For additional information, go to the Centers for Disease Control and Prevention website.

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