What if patients with Lyme disease who have the characteristic rash are not diagnosed and treated?
In that circumstance the rash will resolve within about one month. However, over the course of the next months slightly more than half of such individuals will go on to develop a type of arthritis affecting the knee or other large joint, and about 10 percent to 20 percent will develop neurological problems or an abnormally slow heart rate. These patients may require up to 28 days of antibiotic therapy.
