What Is Lyme Disease?
Lyme disease is the most common vector-borne illness in the United States, with approximately 476,000 cases diagnosed each year. It is caused by the bacterium Borrelia burgdorferi, which is transmitted to humans through the bite of infected deer ticks (black-legged ticks).
Lyme disease is most common in the Northeast, Mid-Atlantic, and upper Midwest, but cases have been reported in all 50 states. Early detection and treatment are critical for a full recovery.
Lyme Disease Symptoms by Stage
1Early Localized (3–30 days after bite)
- •Erythema migrans (EM) rash — red, expanding, often bullseye-shaped
- •Rash appears at the bite site in 70–80% of infected people
- •Fever and chills
- •Headache and fatigue
- •Muscle and joint aches
- •Swollen lymph nodes
2Early Disseminated (days to weeks)
- •Additional EM rashes on other areas of the body
- •Facial palsy (loss of muscle tone on one or both sides of the face)
- •Severe headaches and neck stiffness (meningitis)
- •Heart palpitations or irregular heartbeat (Lyme carditis)
- •Shooting pain, numbness, or tingling in hands or feet
- •Episodes of dizziness or shortness of breath
3Late Disseminated (weeks to months)
- •Severe joint pain and swelling, especially in the knees (Lyme arthritis)
- •Numbness or tingling in hands, feet, or back
- •Cognitive problems — difficulty concentrating, memory issues ('brain fog')
- •Chronic fatigue
- •Sleep disturbances
Diagnosis & Treatment
Diagnosis
Lyme disease is diagnosed based on symptoms, physical findings (such as the EM rash), and the possibility of exposure to infected ticks. Lab tests (ELISA followed by Western blot) can help confirm the diagnosis but may not be positive in the first few weeks after infection.
Treatment
Most cases of Lyme disease are successfully treated with 2–4 weeks of oral antibiotics:
- Doxycycline — Most commonly prescribed for adults and children over 8
- Amoxicillin — Used for younger children and pregnant women
- Cefuroxime axetil — Alternative when doxycycline or amoxicillin can't be used
Post-Treatment Lyme Disease Syndrome
About 10–20% of patients experience lingering symptoms (fatigue, pain, joint or muscle aches) after treatment. This is called Post-Treatment Lyme Disease Syndrome (PTLDS). The cause is not fully understood, and additional antibiotic treatment has not been shown to help.
How to Prevent Lyme Disease
- 1
Avoid tick habitats
Stay on trails. Avoid tall grass, leaf litter, and wooded areas where deer ticks live.
- 2
Use repellent
Apply DEET (20–30%) to skin and permethrin (0.5%) to clothing, shoes, and gear.
- 3
Wear protective clothing
Long sleeves, long pants tucked into socks, and light-colored clothing to spot ticks easily.
- 4
Do daily tick checks
Check your entire body after being outdoors. Pay special attention to the scalp, armpits, groin, and behind the ears.
- 5
Remove ticks promptly
Removing a tick within 24 hours greatly reduces the risk of Lyme transmission. Use fine-tipped tweezers.
- 6
Treat your yard
Keep grass short, remove leaf litter, and consider professional tick control for your property.
Highest-Risk States for Lyme Disease
The CDC reports that 95% of confirmed Lyme disease cases come from 15 states, concentrated in the Northeast and upper Midwest.
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