Lyme disease

`Lyme disease is caused by the spirochaete Borrelia burgdorferi and is spread by ticks. 
 
Early features (within 30 days) 
 

  • erythema migrans 

    • 'bulls-eye' rash is typically at the site of the tick bite 

    • typically develops 1-4 weeks after the initial bite but may present sooner 

    • usually painless, more than 5 cm in diameter and slowlly increases in size 

    • present in around 80% of patients. 

  • systemic features 

    • headache 

    • lethargy 

    • fever 

    • arthralgia 

 
 

 
Later features (after 30 days) 
 

  • cardiovascular 

    • heart block 

    • peri/myocarditis 

  • neurological 

    • facial nerve palsy 

    • radicular pain 

    • meningitis 

 
 

 
Investigation 
 

  • NICE recommend that Lyme disease can be diagnosed clinically if erythema migrans is present 

    • erythema migrans is therefore an indication to start antibiotics 

  • enzyme-linked immunosorbent assay (ELISA) antibodies to Borrelia burgdorferi are the first-line test 

    • if negative and Lyme disease is still suspected in people tested within 4 weeks from symptom onset, repeat the ELISA 4-6 weeks after the first ELISA test. If still suspected in people who have had symptoms for 12 weeks or more then an immunoblot test should be done 

    • if positive or equivocal then an immunoblot test for Lyme disease should be done 

 
Management of asymptomatic tick bites 
 

  • tick bites can be a relatively common presentation to GP practices, and can cause significant anxiety 

  • if the tick is still present, the best way to remove it is using fine-tipped tweezers, grasping the tick as close to the skin as possible and pulling upwards firmly. The area should be washed following. 

  • NICE guidance does not recommend routine antibiotic treatment to patients who've suffered a tick bite 

 
Management of suspected/confirmed Lyme disease 
 

  • doxycycline if early disease. Amoxicillin is an alternative if doxycycline is contraindicated (e.g. pregnancy) 

    • people with erythema migrans should be commenced on antibiotic without the need for further tests 

  • ceftriaxone if disseminated disease 

  • Jarisch-Herxheimer reaction is sometimes seen after initiating therapy: fever, rash, tachycardia after first dose of antibiotic (more commonly seen in syphilis, another spirochaetal disease)