Not every tick bite causes Lyme disease. The rash starts as a small red round area which usually spreads to two or more inches across. Other symptoms are fever, headache, tiredness, stiff neck, joint pain, and swollen lymph nodes. Without treatment, the heart, nervous system, or joints may be affected weeks to months later. A person can get Lyme disease more than once.
Blood tests are available Blood tests done in the early stage of illness can be negative.
In the early stage, diagnosis is usually based on signs and symptoms. Blood tests are usually positive after 30 days. The tests may stay negative in persons who were treated early with antibiotics. A doctor may treat Lyme disease with antibiotics based on a person's illness and a history of a tick bite or tick exposure. Early treatment will prevent later complications.