Erythema migrans is often the only symptom of Lyme disease. It is also the most common symptom. The rash gradually spreads from the site of the tick bite. It is rarely very itchy and does not often cause pain.
It can have a well-demarcated leading edge, and the central area of the rash can start to clear, giving a target-like appearance, although many rashes are more homogeneous in appearance. If left untreated the rash can cover a large area and last for some weeks.
Another symptom that patients may suffer is ‘flu-like symptoms. There are also a number of more serious symptoms. These may appear in some untreated patients in the following weeks or months. These symptoms can affect the nervous system, joints and rarely the heart or other tissues. (4)