Questionnaire/history: Tick bite? - Date and time? - Location? - If bitten by a tick whilst abroad possibility of other tick-borne diseases (or co-infection)? - Tick completely removed? Eyrthema migrans? - Onset? - < 3 days after (suspected) tick bite? - 1-4 weeks (3 days to 3 months) after tick bite? - Round or oval in shape? - Pink, red or purple in colour? - Flat? - Vesicle or pustule at the centre (in 5%)? - Border may be slightly raised? - Central clearing or a target-like appearance (in 65–80% of people infected in Europe, but in only 20–35% of those infected in the US) or uniformly red (more common in the US)? - Expands over days to weeks (usually)? - Diameter larger than 5 cm (median 16 cm, can be 1 m)? - Itchy, hot or painful (usually not)? - Secondary (or disseminated) erythema migrans (may occur following haematogenous dissemination of infection, resulting in multiple lesions, usually smaller than 5 cm)? Differential diagnosis Associated symptoms? - Onset? - Flu-like symptoms (in Europe in 1/3 of cases, in the US more common)? - Fever? - Sweats? - Malaise? - Tiredness? - Swollen glands? - Nausea/vomiting? - Joint or muscle aches and pain? - Headache? - Neck pain or stiffness? - Cognitive impairment (such as memory problems and difficulty concentrating)? - Eye symptoms (eg uveitis or keratitis)? - Cardiac problems (eg heart block or pericarditis)? - Skin rashes (eg acrodermatitis chronica atrophicans or lymphocytoma)? - Neurological features (rarely, usually later in the disease)? - Abnormal sensation like tingling or pricking (‘pins and needles’) (paraesthesia)? - Mononeuritis multiplex or other unexplained radiculopathy? - Facial palsy or other unexplained cranial palsies? - Meningitis? - Encephalitis? - Neuropsychiatric presentations or unexplained white matter changes on brain imaging? Management Reference(s): NICE CKS: Lyme disease Information for patient/carer(s): NHS Health A to Z: Lyme disease Patient UK: Lyme disease