Marcia is a 33 year old lady who has come to her GP surgery as she has developed an unusual rash on her right leg after a UK family holiday to the New Forest. She is pretty sure she was bitten by a tick. She first noticed the rash five days ago and thinks it is worsening. She is otherwise well in herself and no one else who went on the trip is affected. She has no other past medical history of note, is a non-smoker and does not drink any alcohol.
On examination there is a erythematous circular lesion with central clearing that is 7cm in diameter. Observations are within normal limits and systems examination is otherwise unremarkable.
What is the next most appropriate step: