Tuesday, June 17, 2008

Rash

It is early summer. I am seeing a lot of Lyme rashes. They are called Erythema Chronicum Migrans. They are not bulls eye rashes. The are generally red rashes with a circumscribed border, but not necessarily round. Most rashes are on the upper and lower extremities or the trunk. They can occur anywhere on the skin.The outside borders or the rashes may be more active and there may be a tendency for central clearing, but is usually not seen until the rash has been present for several weeks. Some rashes have an atypical color. They can appear purplish rather than red. The rashes can be flat, but may be slightly raised. Most of the rashes are large, greater than 5cm in diameter, but the sizes vary. Very rarely is a history of tick bite recalled. Since many if not most cases of Lyme disease do not present with this rash, one can imagining that many folks are presently getting infected without any awareness. Because of the increased awareness in the public, most patients come in early. Most have no symptoms except for the rash. Some have mild flu like symptoms, headache, stiff neck and mild muscle and joint pain. This is stage one Lyme disease. Since there are many patients who have been treated for stage one disease who still develop chronic Lyme down the road I like to err on the side of over aggressive treatment. Although there is no scientific basis for this, I like to treat with Doxycycline and Amoxicillin for 30 days. I would continue treatment if any traces of the rash persist. For patients for whom photosensitivity is likely to be a problem I treat with Amoxicillin or Ceftin alone for 30 days. Since other drugs commonly used for chronic Lyme, the macrolides, Zithromax and Biaxin really require concomitant Plaquenil, I do not use these drugs, it seems like too much for stage on Lyme which should respond to a singe antibiotic agent. Some doctors still treat for 10 days, two weeks or even 6 weeks. I use high doses and treat for 30 days. I tell the patients the symptoms of persistent Lyme and ask them to come back in if any of these symptoms develop. It is a mistake to do blood work in these patients. Lyme antibodies may not turn positive for 4 to 6 weeks. C6 peptide antibodies may turn positive more quickly. Some doctors check C3a and C4a as evidence of acute infection. I think this is a clinical diagnosis and do not recommend lab testing which will be unhelpful or even misleading.

No comments: