Lyme disease is a bacterial infection caused by Borrelia species and transmitted to humans through the bite of infected black-legged ticks (commonly known as deer ticks). It often begins with a characteristic expanding skin rash called erythema migrans, which may resemble a bull’s-eye pattern, along with symptoms such as fever, fatigue, headache, and muscle or joint aches. If untreated, the infection can spread to the joints, heart, and nervous system, leading to more serious complications such as arthritis, facial paralysis, or irregular heartbeat. Lyme disease is most common in wooded or grassy areas where ticks are prevalent. Early recognition and prompt medical evaluation are important to reduce the risk of long-term complications.