Fleas
Fleas are a nuisance to their hosts, causing an itching sensation which in turn frequently results in the host attempting to remove the pest by biting, pecking, scratching, etc. Fleas are not simply a source of annoyance, however. Some people and animals suffer allergic reactions to flea saliva, resulting in rashes and other skin irritations. Flea bites generally result in the formation of a slightly raised, swollen itching spot with a single puncture point at the centre (not unlike a mosquito bite).