Untreated Lyme disease can produce a wide range of symptoms, depending on the stage of infection. According to the U.S. Centers for Disease Control and Prevention, these include fever, rash, facial paralysis, and arthritis.

Seek medical attention if you observe any of these symptoms and have had a tick bite, live in an area known for Lyme disease, or have recently traveled to an area where Lyme disease occurs:

1. Fever, chills, headache, fatigue, muscle and joint aches, and swollen lymph nodes may occur in the absence of rash.

2. Erythema migrans (EM) rash (see photos here) occurs in approximately 70 to 80% of infected persons. Begins at the site of a tick bite after a delay of 3 to 30 days (average is about 7 days). It expands gradually over several days reaching up to 12 inches or more across. May feel warm to the touch but is rarely itchy or painful. Sometimes clears as it enlarges, resulting in a target or “bull’s-eye” appearance. May appear on any area of the body. And it does not always appear as a “classic” erythema migrans rash.

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3. Severe headaches and neck stiffness.

4. Additional EM rashes on other areas of the body.

5. Facial palsy (loss of muscle tone or droop on one or both sides of the face).

6. Arthritis with severe joint pain and swelling, particularly the knees and other large joints.

7. Intermittent pain in tendons, muscles, joints, and bones.

8. Heart palpitations or an irregular heart beat (Lyme carditis).

9. Episodes of dizziness or shortness of breath.

10. Inflammation of the brain and spinal cord.

11. Nerve pain.

12. Shooting pains, numbness, or tingling in the hands or feet.