Clinical presentation of Lyme disease and progression of symptoms can vary widely among individuals. After an infected tick bite, most individuals (70-80%) initially present the characteristic large, red, expanding rash of Lyme disease known as erythema migrans. It often, but not always, takes on the appearance of a bull's eye target (Figure 6). Average appearance is between 4 and 14 days, but a range of 3 to 30 days is possible.

Figure 6

Some infected individuals present with acute illness manifested by fever, fatigue, aches and pains, with or without the erythema migrans rash, and less often with specific neurological or musculoskeletal manifestations. Others may not manifest any signs or symptoms of disease other than erythema migrans, some develop only flu-like symptoms and in some cases there are no recognizable symptoms.

Typically, the symptoms of Lyme disease are divided into three stages. (Figure 7)

Figure 7

The clinical manifestations of illness can be divided into three stages as follows: Stage 1 is predominantly characterized by: erythema migrans (EM), a skin rash at the site of the tick bite that classically begins as a single small red spot that expands to resemble a bull's-eye target — only 70%-80% of infected individuals have this sign. flulike symptoms — malaise and fatigue, headache, fever and chills, myalgia, and arthralgia Early signs and symptoms are typically intermittent and changing Stage 2 is characterized by: hematogenous dissemination; neurological involvement (particularly meningoencephalitis) which is most often manifest by headache and neck pain and stiffness; and, cardiovascular involvement (endocarditis). Stage 3 is characterized by: persistent infection; recurrent migratory arthritis, primarily of the large joints — this the classic feature of stage 3 infection; other musculoskeletal syndromes including: myositis, diffuse fasciitis, osteomyelitis, and panniculities; and, chronic neurological involvement.