Lyme Disease: Causes, Symptoms, Prevention, and Research Perspectives

Risk factors

Many environmental and behavioral factors can increase the risk of Lyme disease infection. Exposure to wooded, grassy, or brushy environments, especially in endemic areas, increases the chance of contact with infected ticks. Activities such as hiking, fishing, gardening, or hunting can expose individuals to close contact with ticks.

The disease is most common in regions such as the northeastern United States, the upper Midwest, southern Canada, and parts of Europe, where infected ticks are common. Ticks are most active during the warmer months, from spring to early fall, but they can be active any time temperatures are above freezing. Wearing revealing clothing, not using repellent, or not thoroughly checking skin after outdoor activities also increase the risk.

Complications

If Lyme disease is not recognized and treated early, complications can occur that affect multiple body systems. One of the most common long-term effects is chronic arthritis, particularly in large joints like the knees. Joint pain may persist or recur, leading to swelling and limited mobility.

Neurological problems are another complication, ranging from peripheral neuropathy (nerve damage causing pain or numbness) to memory and cognitive problems known as "brain fog."

In some cases, the heart may be affected, manifesting as an electrical conduction disorder called Lyme disease. A subgroup of patients may develop Post-Treatment Lyme Disease Syndrome (PTLDS), in which fatigue, muscle pain, or cognitive difficulties persist for months after antibiotic treatment ends.

Researchers are still investigating whether PTLDS is caused by bacterial remnants, immune system dysregulation, or other mechanisms. Some scientists are exploring the potential peptides used exclusively in research to better understand the inflammatory and immune processes that may play a role in these long-term effects, although this work is still experimental and has not been clinically confirmed.

When to see a doctor

Prompt medical attention is crucial if you suspect you have been bitten by a tick or if you develop symptoms suggestive of Lyme disease, especially after being in high-risk areas.

Even if you don't remember being bitten by a tick, the appearance of symptoms such as a rash, fever, fatigue, joint pain, or facial weakness should prompt a visit to the doctor. Early diagnosis can prevent the disease from progressing to more serious stages. For those who have already been diagnosed and treated but still experience persistent symptoms, follow-up care is important.

Although PTLDS symptoms usually improve over time, patients should consult a doctor if symptoms persist or worsen, especially if neurological or cardiac symptoms are present.

Prevention

Lyme disease prevention begins with limiting your exposure to ticks. When walking in wooded or grassy areas, wear light-colored clothing to make it easier to spot and remove ticks. Tuck long pants into your socks and wear long-sleeved shirts to minimize exposed skin.

Use repellents approved by the Environmental Protection Agency (EPA), containing DEET, picaridin, or permethrin, which can be applied to skin and clothing. After outdoor activities, thoroughly inspect your body, especially underarms, behind the knees, around the waist, hairline, and other warm, hidden places where ticks like to attach.

Showering soon after returning home can help remove unattached ticks. Wash and dry outdoor clothing on high heat to kill any ticks hidden in the fabric. Also, check pets after returning from outdoors, as they may bring ticks home.