Lyme disease is caused by four main species of bacteria. Borrelia burgdorferi and Borrelia mayonii cause Lyme disease in the United States, while Borrelia afzelii and Borrelia garinii are the leading causes in Europe and Asia. The most common tick-borne illness in these regions, Lyme disease is transmitted by the bite of an infected black-legged tick, commonly known as a deer tick.
You’re more likely to get Lyme disease if you live or spend time in grassy and heavily wooded areas where ticks carrying Lyme disease thrive. It’s important to take common-sense precautions in tick-infested areas.
The signs and symptoms of Lyme disease vary. They usually appear in stages, but the stages can overlap.
Early signs and symptoms
A small, red bump, similar to the bump of a mosquito bite, often appears at the site of a tick bite or tick removal and resolves over a few days. This normal occurrence doesn’t indicate Lyme disease.
However, these signs and symptoms can occur within a month after you’ve been infected:
- Rash. From three to 30 days after an infected tick bite, an expanding red area might appear that sometimes clears in the center, forming a bull’s-eye pattern. The rash (erythema migrans) expands slowly over days and can spread to 12 inches (30 centimeters) across. It’s typically not itchy or painful but might feel warm to the touch.
Erythema migrans is one of the hallmarks of Lyme disease, although not everyone with Lyme disease develops the rash. Some people develop this rash at more than one place on their bodies.
- Other symptoms