The role of the allergist in Lyme disease.

The allergist may frequently be involved with cases of Lyme disease. There are at least three reasons for this. First, the major symptom is often a rash that brings into the differential diagnosis several diseases that the allergist is likely to have expertise in; therefore, the allergist's role as a diagnostician is very important. The second reason is that the Borrelia burgdorferi (Bb) infection is treated with antibiotics and the patients may frequently develop reactions that may be immune-mediated. The allergist's expertise in diagnosis and management of allergic reactions is important. The third reason is that there is no established laboratory diagnostic test so that the clinician must use the existing tests, most often serologic, with their limitations, in the context of a history and physical. The allergist as an immunologist can be very helpful in the proper interpretation of the test results. The differential of the rash and the immune response to the infecting agent is described.