Signs and Symptoms of Bedbug Bites

In This Article

A bedbug bite is similar to bites from other species of bugs. There is little that differentiates the actual bite mark. Because of this, bedbug bites are often misdiagnosed as either coming from other species or as being skin rashes unrelated to bug bites at all.

bedbug bites symptoms
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Common Symptoms


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 properties. In some people, this saliva might cause reactions, including itching.

Bedbugs are a species of insect known as cimex lectularius (literallycimex is Latin for bug and lactularius 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. There are published reports, many without supporting evidence, that each of the common bedbug species has chemically different saliva. Some researchers, however, have found no difference in the reactions caused by each species.

Small, Red Lesions

Bedbug bites are small, red lesions that usually grow to no more than 5mm wide. The lesions, or weals, start off as red areas that become raised then develop into blisters. They itch and scratching is said to make the itching worse.

Often, bedbug bites are clustered along lines usually following arms and legs.

Bedbug bites often appear in a straight line or row. Theories for this range from the idea that bedbugs are feeding along blood vessels to the idea that bedbugs remain with their bodies touching the bedding while they feed, and the bugs are left to feed only along lines where the skin is touching the bedding in just the right manner.

This photo contains content that some people may find graphic or disturbing.

Bed bug bites
 Joel Carillet / Getty Images 

Rare Symptoms

Large bedbug bite clusters can cover significant portions of the body and make it look as if the patient has chickenpox. If the clusters of bites are close enough together, the bites can become confluent, appearing to be one large rash.

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.

Patients with chronic, large clusters of bedbug bites can develop fatigue and fever, but these are very rare.

Some patients develop blisters filled with blood or bloody fluid, especially on the arms and legs. These blood blisters are extremely rare and can burst, causing bleeding or oozing of the bloody fluid.

Healthcare providers are not sure if the cause of these blisters is related to the bug or the human but have found groups of patients that were all bitten by bugs on the same train exhibiting this sign.

Signs of Infestation

Bedbug bites can easily be confused with the generic red blisters caused by other bug and insect bites. For this reason, finding signs of an infestation is an important part of confirming a diagnosis.

Bedbugs like to infest folds of cushions and upholstery on furniture and in mattresses.

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.

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.

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Article Sources
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  2. Bed bugs: Diagnosis and treatment. Published 2019.

  3. Studdiford JS, Conniff KM, Trayes KP, Tully AS. Bedbug infestation. Am Fam Physician. 2012;86(7):653-8.

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