From the Research
A tick bite on physical exam is typically characterized by a ring-shaped skin lesion, erythema migrans, which is centred on the bite and expands outwards, usually appearing within two weeks after a bite from an infected tick 1. When examining a patient with a tick bite, it is essential to look for signs of erythema migrans, which can be a characteristic skin lesion with a central punctum where the tick's mouthparts penetrated the skin. The lesion may be surrounded by erythema and can exhibit mild local swelling or induration.
- Key features to document include:
- Location of the bite on the body
- Size of the lesion (measured in millimeters)
- Presence of any surrounding erythema or rash
- Evidence of secondary infection such as increased warmth, purulence, or lymphangitis
- Any expanding circular rash (erythema migrans) which could indicate Lyme disease, typically appearing 3-30 days after the bite as a bull's-eye pattern with central clearing, as described in the study by Prescrire international 1 It is crucial to carefully document these findings, as tick bites can transmit various pathogens causing diseases with different clinical presentations, and monitoring for potential development of tick-borne illnesses is essential for guiding appropriate treatment decisions.