Little is known of the host and the bacteria response in vivo in patients with Lyme disease. In an attempt to better understand the pathology of erythema migrans (EM), we will use DNA microarrays to characterize gene expression patterns in skin biopsies from individuals with a diagnosis of EM and compared those to the patterns of gene expression seen in biopsies from normal, unaffected individuals. Biopsies from patients may also be evaluated for B. burgdorferi gene expression using microarrays. Patients diagnosed with erythema migrans will have 4 4-mm punch skin biopsies of affected area, and will return for 4 follow up visits in the course of a year. Therapy for Lyme disease will be offered. Healthy volunteers will have a screening visit, a visit for the skin biopsies and a follow up visit. Patients and healthy volunteers will be compensated for their time and inconvenience.

• INCLUSION CRITERIA:

Patients:

Age greater than or equal to 18 years

Diagnosis of EM - an expanding annular lesion, at least 5 cm in diameter on a person with a history of exposure to the disease.

Exposure is defined as having been (less than or equal to 30 days before onset of EM) in wooded, brushy, or grassy areas (i.e., potential tick habitats) in an area in which Lyme disease is endemic.

A history of tick bite is not required.

The area of the erythema migrans lesion is suitable for biopsy. This excludes biopsies on the face, neck, scalp, and over the tibia.

Not know to be positive for RPR, HIV, HBsAg or HCV

Able to give consent

Health Volunteers:

Age greater than or equal to 18 years

Not positive for RPR, HIV, HBsAg or HCV.

Able to give consent

EXCLUSION CRITERIA:

Patients:

Antibiotic therapy for the current episode of Lyme disease

Oral corticosteroids within the past 2 weeks

History of severe skin disease (such as psoriasis, atopic dermatitis) in the last year.

Diagnosis of diabetes, active cancer, or autoimmune diseases.

Investigational drugs in the past month

History of forming large thick scars after skin injuries or surgery

History of excessive bleeding after cuts or procedures or on anticoagulation.

Use of steroid cream/ointment at the rash.

Health Volunteers:

History of Lyme disease, or serological evidence for Lyme disease

No oral corticosteroids within the past 2 weeks

History of severe skin disease (such as psoriasis, atopic dermatitis) in the last year.

Diagnosis of diabetes, cancer, autoimmune diseases.

Investigational drugs in the past month

History of forming large thick scars after skin injuries or surgery

No history of excessive bleeding after cuts or procedures or on anticoagulation.