Two factors that make Lyme disease hard to diagnose Lyme disease commonly presents like many other illnesses including the flu. This factor alone makes it hard to differentiate the symptoms of Lyme disease. Another factor that makes Lyme disease hard to diagnose is the lack of training among doctors. Doctors who reside in states with a high incidence of Lyme disease cases (northeastern U.S.) are more experienced. On the other hand, in states where Lyme disease is not as prevalent (California for example) diagnoses of the illness may take much longer. However, when a patient suffering from Lyme disease develops a bulls-eye rash, the illness is easier to spot. The problem is many patients don’t develop this rash or it’s not noticeable.