Not everyone infected with Lyme Disease gets the classic Lyme bull's eye rash. In fact less than 50% of those infected get a bull's eye. Some get no rash at all, while others may get another type of rash. Rashes can occur at sites other than the bite. Many of those infected don't recall finding a bite prior to illness onset.
The average Lyme sufferer if not diagnosed early can see 20-30 doctors or more before being properly diagnosed.
One of the biggest issues with diagnosing this disease is the lack of sufficient testing. The most common tests used to date are the Elisa test which misses 40%-80% of cases. The Western Blot which is a little more reliable providing it is performed by the right lab such as Igenex in CA. However even the Western Blot misses a large amount of cases. There is also the Lyme PCR test which looks for the DNA of the lyme bacteria in the blood. The problem with this test is Lyme bacteria usually isn't found in the blood but mainly in tissue . The lack of proper testing is the reason that experts in this area strongly feel that Lyme should be diagnosed based on clinical presentation i.e. symptoms and patient history and only confirmed by a positive test result.
AGAIN: There are faults with all of these tests. The tests can only help support the diagnosis of Lyme Disease, but should not be the deciding factor. The diagnosis should rely heavily on the symptoms and possibilty of exposure to the disease.
For more about lyme disease testing see the link below. Igenex