Lyme Disease: An Overview

Abstract

Lyme disease, a tick-borne multisystem disease, is caused by spirochete Borrelia burgdorferi (sensu lato). It is a common illness in temperate countries, especially the United States, but the incidence is increasing across continents due to increasing reforestation, travel and adventure tourism, increased intrusion in the vector habitat, and changing habitat of the vector. Transmission primarily occurs via bite of an infected tick (Ixodes spp.). The appearance of an erythema migrans rash following a tick bite is diagnostic of early Lyme disease even without laboratory evidence. Borrelia lymphocytoma and acrodermatitis chronica atrophicans along with multisystem involvement occur in late disseminated and chronic stages. A two-step serologic testing protocol using an enzyme-linked immunosorbent assay (ELISA) followed by confirmation of positive and equivocal results by Western immunoblot is recommended for the diagnosis. Transplacental transmission to infant occurs in the first trimester with possible congenital Lyme disease making treatment imperative during antenatal period. The treatment is most effective in the early stages of the disease, whereas rheumatological, neurological, or other late manifestations remain difficult to treat with antibiotics alone. Treatment with oral doxycycline is preferred for its additional activity against other tick-borne illnesses which may occur concurrently in 10%-15% of cases. New-generation cephalosporins and azithromycin are alternative options in patients with doxycycline contraindications. No vaccine is available and one episode of the disease will not confer life-long immunity; thus, preventive measures remain a priority. The concept of post-Lyme disease syndrome versus chronic Lyme disease remains contested for want of robust evidence favoring benefits of prolonged antibiotic therapy.

Keywords: Acrodermatitis chronica atrophicans; Borrelia; Ixodes; Lyme borreliosis; borrelia lymphocytoma; erythema migrans.

Figure 1

Erythema migrans over the thigh in a 36-year-old woman

Figure 2

Borrelia lymphocytoma cutis involving the ear lobe in a 12-year-old boy (encircled area is post biopsy)

Figure 3

Acrodermatitis chronica atrophicans in a 60-year-old man involving cool dorsal surfaces of the upper extremities

Figure 4

Characteristic papery thin patches coalescing into large areas of finely wrinkled atrophic skin bereft of hair in acrodermatitis chronica atrophicans involving the lower limbs

Figure 5

(a) Large, ill-defined, bluish-red erythematous patch with tendency to spread peripherally over the lower trunk and (b) back of upper thighs. Note concurrently occurring fibrotic papulonodules over the patch and near the joints, mainly around the elbows and sacroiliac joints