Lyme disease, also known as borreliosis, is the most common tick-borne illness. Typical symptoms include headache, fatigue, fever, and skin rash.
Not all ticks can transmit Lyme disease. Only black-legged, castor bean, and taiga ticks are known to transmit the bacteria that cause Lyme disease. They spread the disease by biting humans and other animals.
Bacteria that can cause Lyme disease include Borrelia burgdorferi, B. mayonii, B. afzelii, and B. garinii.
This article includes information on the progression of the tick-borne disease and guidance on when to see a doctor.
Risk factors for Lyme disease include:
- work environment
- participation in outdoor activities
- geographical area
- time of year
People who work outside are more likely to get tick bites. Those who enjoy outdoor recreation, such as camping and hiking, are also at higher risk for tick bites.
In the United States, most cases of Lyme disease occur in the northeast and mid-Atlantic, the north central states, and the west coast.
Ticks that carry the bacteria that cause Lyme disease can be active year-round, but they are typically most active during spring and summer.
Not all ticks transmit Lyme disease, and a tick will usually need to remain attached to its host for at least 24 hours to pass on the Lyme bacteria.
A tick bite is the only known way to contract Lyme disease. The bacterium does not spread via sexual intercourse or breast milk.
According to the Centers for Disease Control and Prevention (CDC), an estimated 300,000 cases of Lyme disease occur on a yearly basis in the U.S.
When heading outdoors, people can take simple precautions to avoid tick bites, including using bug spray, checking the body regularly for ticks, and wearing long pants and long-sleeved shirts.
Most symptoms that appear within a few days after a Lyme-infected tick bite include:
- joint and muscle aches
- swollen lymph nodes
In up to 80% of people with Lyme disease, an erythema migrans (EM) rash appears between 3 and 30 days after the tick bite. It shows up at the site of the bite, usually within a week, and grows bigger over time.
The rash sometimes takes on a “bull’s-eye” appearance. While it is an apparent sign of Lyme disease, it does not show up on everyone. It can also sometimes be difficult to detect in people with darker skin tones.
- neck stiffness and bad headaches
- new body rashes
- generalized body aches and pains
- facial muscle weakness or palsy (drooping on one or both sides of the face)
- irregular heart rhythm with palpitations
- shortness of breath
- nerve pain and other types of shooting pain or tingling in the hands and feet
- brain and spinal cord inflammation
People with Lyme disease may experience one or several of these later stage symptoms.
Possible complications of Lyme disease include:
- heart problems, such as myocarditis or pericarditis
- joint inflammation with large amounts of fluid, for example, Baker’s cyst in the knee
- neurological problems, such as meningitis, cognitive difficulties, or encephalitis
Lyme carditis is a severe complication of Lyme disease that occurs when the Lyme bacteria enter the heart. People with Lyme carditis may experience heart palpitations, chest pain, shortness of breath, or fainting, in addition to other symptoms of the disease.
About 10% of people with Lyme develop posttreatment Lyme disease syndrome (PTLDS), or chronic Lyme disease, a condition in which certain symptoms of the disease linger after the completion of a course of treatment. Definitive research on the cause of PTLDS has yet to take place.
In addition to complications, coinfection is a possibility. According to the CDC, coinfection — when a tick passes another disease over along with Lyme — occurs in up to 12% of cases. Ticks that transmit Lyme disease sometimes carry other diseases, such as babesiosis and anaplasmosis.
People with Lyme disease usually recover quickly with early intervention. A short course of oral antibiotics is effective in most cases. A doctor will usually prescribe a course of antibiotics that lasts about 2–3 weeks.
The National Institute of Allergy and Infectious Diseases suggest that additional courses of intravenous (IV) antibiotics do not have any benefit.
A person should see a doctor if they have a tick bite or have been in a tick-prone area and experience any of the above symptoms.
Some symptoms may take time to develop, or a person may not have noticed the tick, and it may have fallen off their body before they have any symptoms.
The CDC suggest that people not bring ticks in for testing. Tick testing facilities may not have vigorous quality control standards.
Lyme disease is the most common vector-borne disease. The number of cases of Lyme in the U.S. seems to be steadily increasing.
Lyme disease can cause a range of early symptoms, such as headache, fatigue, fever, and skin rash, while other symptoms may take longer to manifest.