Early localized infection
The classic sign of early local infection with Lyme disease is a circular, outwardly expanding rash called erythema chronicum migrans (also erythema migrans or EM), which occurs at the site of the tick bite three to thirty days after the tick bite. The rash is red, and may be warm, but is generally painless. Classically, the innermost portion remains dark red and becomes indurated (is thicker and firmer); the outer edge remains red; and the portion in between clears, giving the appearance of a bullseye. However, partial clearing is uncommon, and the bullseye pattern more often involves central redness.
EM is thought to occur in about 80% of infected patients. Patients can also experience flu-like symptoms, such as headache, muscle soreness, fever, and malaise. Lyme disease can progress to later stages even in patients who do not develop a rash.
Early disseminated infection
Within days to weeks after the onset of local infection, the Borrelia bacteria may begin to spread through the bloodstream. EM may develop at sites across the body that bear no relation to the original tick bite. Another skin condition that is apparently absent in North American patients, but occurs in Europe, is borrelial lymphocytoma, a purplish lump that develops on the ear lobe, nipple, or scrotum. Other discrete symptoms include migrating pain in muscles, joints, and tendons, and heart palpitations and dizziness caused by changes in heartbeat.
Various acute neurological problems, termed neuroborreliosis, appear in 10?15% of untreated patients. These include facial palsy, which is the loss of muscle tone on one or both sides of the face, as well as meningitis, which involves severe headaches, neck stiffness, and sensitivity to light.
Radiculoneuritis causes shooting pains that may interfere with sleep, as well as abnormal skin sensations. Mild encephalitis may lead to memory loss, sleep disturbances, or mood changes. In addition, some case reports have described altered mental status as the only symptom seen in a few cases of early neuroborreliosis.
The disease may also have cardiac manifestations such as AV block.
Late persistent infection
After several months, untreated or inadequately treated patients may go on to develop severe and chronic symptoms that affect many parts of the body, including the brain, nerves, eyes, joints and heart. Many disabling symptoms can occur, including permanent paraplegia in the most extreme cases.
Chronic neurologic symptoms occur in up to 5% of untreated patients.
A polyneuropathy that involves shooting pains, numbness, and tingling in the hands or feet may develop. A neurologic syndrome called Lyme encephalopathy is associated with subtle cognitive problems, such as difficulties with concentration and short-term memory. These patients may also experience profound fatigue. However, other problems, such as depression and fibromyalgia, are no more common in people who have been infected with Lyme than in the general population.
Chronic encephalomyelitis, which may be progressive, can involve cognitive impairment, weakness in the legs, awkward gait, facial palsy, bladder problems, vertigo, and back pain. In rare cases untreated Lyme disease may cause frank psychosis, which has been mis-diagnosed as schizophrenia or bipolar disorder. Panic attacks and anxiety can occur; there may also be delusional behavior, including somatoform delusions, sometimes accompanied by a depersonalization or derealization syndrome, where the patients begin to feel detached from themselves or from reality.
Lyme arthritis usually affects the knees. In a minority of patients, arthritis can occur in other joints, including the ankles, elbows, wrist, hips, and shoulders. Pain is often mild or moderate, usually with swelling at the involved joint. Baker's cysts may form and rupture. In some cases, joint erosion occurs.
Acrodermatitis chronica atrophicans (ACA) is a chronic skin disorder observed primarily in Europe among the elderly. ACA begins as a reddish-blue patch of discolored skin, often on the backs of the hands or feet. The lesion slowly atrophies over several weeks or months, with the skin becoming first thin and wrinkled and then, if untreated, completely dry and hairless.