Tick bite and early Lyme borreliosis

• Published in: BMJ (Online) Vol. 344; no. may14 1; p. e3124
• Main Authors: Duncan, Christopher J A, Carle, George, Seaton, R Andrew
• Format: Journal Article
• Language: English
• Published: England British Medical Journal Publishing Group 14.05.2012; BMJ Publishing Group LTD
• Subjects: Arachnids; Borrelia; Borreliosis; Disease prevention; Epidemiology; Erythema; Humans; Infections; Insect Bites and Stings - diagnosis; Insect Bites and Stings - therapy; Ixodes ricinus; Lyme disease; Lyme Disease - diagnosis; Lyme Disease - therapy; Male; Middle Aged; Physicians; United Kingdom; United Kingdom > UK; United States > US; Scottish Highlands; Europe
• ISSN: 0959-8138; 1756-1833; 1756-1833
• DOI: 10.1136/bmj.e3124

Transmission of pathogenic Borrelia species is unlikely if ticks are attached for <24 hours and unengorged. 2 4 Fig 1 Fully engorged female Ixodes ricinus (courtesy of Dr Alan S Bowman, University of Aberdeen) Clinical features-Erythema migrans (fig 2 ) occurs in 90% of symptomatic Lyme borreliosis 2-40 days after exposure. 2 3 4 Classic erythema migrans is annular with central clearing (differential diagnosis includes ringworm and erythema multiforme), but in the early stages it can be homogenous and easily confused with cellulitis or insect bite hypersensitivity, and multiple lesions can follow haematogenous spread. 4 Non-specific febrile illness without rash occurs in 7% of early Lyme borreliosis in the US. 3 Neuroborreliosis can occur in early infection and usually presents with meningitis or cranial nerve palsies (such as facial nerve). Paired blood samples taken at a four week interval may be required since seroconversion can take several weeks. 2 Asymptomatic individuals with tick bite should not be tested for Lyme borreliosis (false positives occur because of past resolved infection and cross reactive antibodies), nor should they receive prophylactic treatment (see below). Early Lyme borreliosis has a good clinical outcome. 2 3 4 Cure was observed in 95% of those treated for erythema migrans in a prospective study. 5 Non-specific symptoms such as fatigue or headache are common in the general population 6 and are no more likely in people treated for Lyme borreliosis at 6-12 months. 5 7 Give advice on prevention: - Cover skin with long sleeved clothing in forested areas.