Bedbug bites can easily be confused with a rash.3 For this reason, finding signs of an infestation is an important part of confirming a diagnosis.
Bedbugs tend to infest folds of cushions and upholstery on furniture and in mattresses.
Bedbug infestations are characterized by fecal droppings that look like small specks, increasing in frequency the closer you get to the actual harborage. The bugs produce pheromones when they are stressed or in danger. It smells sickly sweet and gets stronger when people are trying to kill the bedbugs.
Bedbugs can show up pretty much anywhere and are likely to be on other soft furniture in rooms where an infestation can be found on one bed or chair.
There can be a tiny amount of bleeding from the center of a bedbug bite after the bug is done eating. The bleeding is self-limiting and will show up on sheets as flecks of blood.
Large bedbug bite clusters can cover significant portions of the body and can look like chickenpox. If the clusters of bites are close enough together, the bites can become confluent, appearing to be one large rash. People who have chronic, large clusters of bedbug bites can develop anemia, which can cause fatigue.
Some people develop blisters, especially on the arms and legs.
Bedbug bites can rarely cause a severe allergic reaction.
Bedbug bites typically cause itchy wheals on the skin, usually with a pinkish or red appearance. Bedbugs are a species of insect known as cimex lectularius (cimex is Latin for bug and lectulo is Latin for bed). There is a second common species of bedbugs known as cimex hemiptera. These are known as the tropical bedbugs, largely staying within 30 degrees of the equator.
Bedbugs have needle-like mouthparts that pierce the skin and allow the bedbugs to feast on blood. To facilitate eating, they secrete saliva that has anticoagulant (blood-thinning) properties. For some people, this saliva might cause reactions, including itching.
Scratching can make the itching worse.
There are published reports, many without supporting evidence, that each of the common bedbug species has chemically different saliva.1 Some researchers, however, have found no difference in the reactions caused by each species.
Small, Red Lesions
Bedbug bites are small, red wheals (swollen marks on the skin) that usually grow to no more than 5 millimeters (mm) wide. The lesions start off as red areas that become raised and then may develop into blisters.
Bedbug bites often appear in a straight line or row. Theories for this pattern include the idea that bedbugs feed along blood vessels or that they feed only along lines where the skin is touching the bedding.
Bedbug bites cause itchy, red wheals on the body, and rarely cause serious issues, such as allergies or anemia. A bedbug bite looks similar to other bug bites—there’s little that differentiates the actual bite mark. Bedbug bites can be mistaken for skin rashes or bites from other bugs.