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.
Bed bug bites are caused primarily by two species of the insect Cimex: Cimex lectularius (the common bed bug) and Cimex hemipterus.[3] Their size ranges between 1 and 7 mm.[7] They spread by crawling between nearby locations or by being carried within personal items.[2] Infestation is rarely due to a lack of hygiene but is more common in high-density areas.[8][2] Diagnosis involves both finding the bugs and the occurrence of compatible symptoms.[5] Bed bugs spend much of their time in dark, hidden locations like mattress seams or cracks in the wall.[2]
Look for bedbug bites. You most likely know a bedbug infestation by a rash that resembles a mosquito bite. Most often these come at night but in an serious infestation they can occur during the day. A bedbug bite unlike a mosquito bite swells and spreads out. Also, the bites can come in lines and also burn unlike a mosquito bite. A mosquito bite stays round and neat looking.[2]
Some preparation is still required (e.g. removal of heat-sensitive items such as aerosol cans, indoor plants and medications), but it is seldom necessary to bag, launder and/or hot dry bedding and clothing since these items will be heated along with other furnishings. Another advantage of heat treatment is that infestations can often be eliminated in one day, rather than over multiple days or weeks. Conversely, heat treatment alone has no lasting (residual) effect should bed bugs be reintroduced into the dwelling. Consequently, some companies recommend concurrently applying residual insecticides. To further minimize reintroduction, occupants are advised to take as few belongings as possible with them while the heat treatment is in progress.    
Bedbugs are most often found in hotels, hostels, shelters, and apartment complexes where lots of people come and go. Because bedbugs hide in small crevices, they can hitch a ride into your home on luggage, pets, furniture, clothing, boxes, and other objects. Bedbugs are found worldwide, but are most common in developing countries. Once rare in North America, they may be on the rise due, in part, to increases in international travel.
Occasionally, you might find other bugs which resemble the common bed bug including the bat bug and swallow bug. Both of these species superficially resemble the common bed bug. However, their primary hosts are bats and birds and there are small but diagnostic morphological differences. Problem infestations with these bugs may occur in attics or unused chimneys. Typically, when one host is gone these bugs seek an alternative host blood meal. This is when humans are bitten. It is important to differentiate between the common bed bug and other bugs that feed on bats and birds because control efforts can be targeted at the wrong sites and infestations can continue.
Bed bugs are tiny, flat, wingless insects that range in color from nearly white to deep brown/reddish. The parasitic pests get their name from their hiding spot of choice – they prefer burrowing into bed frames and mattresses during the day, then become active at night when they feed on people and pets. Bed bugs are resilient pests that can hitch a ride on luggage, furniture, storage boxes, backpacks and clothing (but rarely humans), very quickly causing an infestation.
Bed bug bites: What you need to know Bed bugs are small, parasitic insects that feed on human blood. They often bite humans during the night or early morning when people are asleep. While they don't carry disease, they can cause irritation, sores, and itchiness that might prevent a good night's sleep. Learn how to identify, control, and prevent bed bugs. Read now 
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