A sign has the potential to be objectively observed by someone other than the patient, whereas a symptom does not. There is a correlation between this difference and the difference between the medical history and the physical examination . Symptoms belong only to the history, whereas signs can often belong to both. Clinical signs such as rash and muscle tremors are objectively observable both by the patient and by anyone else. Some signs belong only to the physical examination, because it takes medical expertise to uncover them. (For example, laboratory signs such as hypocalcaemia or neutropenia require blood tests to find.) A sign observed by the patient last week but now gone (such as a resolved rash) was a sign, but it belongs to the medical history, not the physical examination, because the physician cannot independently verify it today.
The hallmark of Lyme disease is for symptoms to mysteriously appear and then disappear weeks later, or for pain to move around the body. It is important to note that you can be infected for years without becoming disabled due to the morphologic nature of the bacteria. In other words, the disease can lie dormant in your body for months or years, taking over when you are worn down physically or if your immune system is suddenly (or gradually) compromised. If you have symptoms in two or more bodily systems, you should consult a "Lyme-literate" doctor.