Lyme Disease - Diagnosis

Diagnosis

Lyme disease is diagnosed clinically based on symptoms, objective physical findings (such as erythema migrans, facial palsy or arthritis) or a history of possible exposure to infected ticks, as well as serological blood tests. The EM rash is not always a bullseye, i.e., it can be red all the way across. When making a diagnosis of Lyme disease, health care providers should consider other diseases that may cause similar illness. Not all patients infected with Lyme disease will develop the characteristic bullseye rash, and many may not recall a tick bite.

Because of the difficulty in culturing Borrelia bacteria in the laboratory, diagnosis of Lyme disease is typically based on the clinical exam findings and a history of exposure to endemic Lyme areas. The EM rash, which does not occur in all cases, is considered sufficient to establish a diagnosis of Lyme disease even when serologic blood tests are negative. Serological testing can be used to support a clinically suspected case, but is not diagnostic by itself.

Diagnosis of late-stage Lyme disease is often complicated by a multifaceted appearance and nonspecific symptoms, prompting one reviewer to call Lyme the new "great imitator." Lyme disease may be misdiagnosed as multiple sclerosis, rheumatoid arthritis, fibromyalgia, chronic fatigue syndrome, lupus, Crohn's disease or other autoimmune and neurodegenerative diseases.