Tick bite

Ticks are blood-sucking parasites which can cause localized injury through direct trauma to skin, or systemic illnesses by acting as vectors for other diseases. These include rickettsial infections (e.g. Rocky Mountain spotted fever), bacterial infections (e.g. Lyme disease) and viral infections (e.g. tick-borne encephalitis). They have also been implicated in alpha-gal allergy, a delayed allergic response to consumption of mammalian meat following bites from certain ticks.

Ticks may be hard or soft, and typically fall off the skin as soon as they become engorged with blood. However, if the tick is still attached to the skin at the time of presentation, it must be gently extracted, pulling upwards and away from the skin using, making sure not to break the mouthparts or squeeze the tick body.

Most tick bites leave no obvious scar, but they are sometimes associated with erythema migrans – a characteristic target-shaped lesion. Occasionally small, erythematous papules form within a few days at the site of the bite. These may harden, blister or even necrose, resulting in an eschar. Some tick species may also cause characteristic cutaneous reactions including urticaria and purpura.

Treatment for tick bites depends on individual symptoms, but includes topical steroids or oral antihistamines for pruritus, and antibiotics for associated cellulitis. Patients should be monitored for signs of systemic disease and, should symptoms arise, be treated accordingly.  Depending on local guidelines, some patients may qualify for prophylaxis of endemic disease e.g. macrolide antibiotics for Lyme disease.