The mechanism of skin injury by arthropods depends on the structure of the mouthparts. These insects are categorized as vessel feeders if they insert the tip into a capillary or as pool feeders if they feed on the extravasated blood from damaged tissue. They often inject different pharmacologically active substances (eg, hyaluronidase, proteases, kinins), which may cause different skin reactions (eg, erythema, wheal, vesicle, hemorrhagic nodule). See the following images.
Should I worry about a tick bite? Ticks are parasites that feed on blood, and although their bites are harmless they can still transmit diseases, such as Lyme disease or Rocky Mountain spotted fever. Learn what ticks are and how to recognize the signs and symptoms of a bite. This MNT Knowledge Center article also explains how to prevent tick bites. Read now