Is Your Rash a Bed Bug Bite or Just Allergies?

How to Tell the Difference Between a Bed Bug Bite and an Allergic Reaction

Bed bug
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Bed bugs, scientific name Cimex lectularius, are a flat wingless insect that can be challenging to rid from your home. Each bed bug is typically about half of a centimeter in length (about half the size of a dime) and may appear brown or red in color. These bugs are blood-sucking parasites that usually feed at night. Bed bugs typically feed on humans, with each feeding lasting about five to 10 minutes.

Bed bugs can go months between meals, making them difficult to eradicate.

These bugs can also be difficult to find since they tend to hide during the day. You may find evidence of a bed bug infestation such as black specks on sheets and mattresses, which are a mix of droppings and other body parts. These insects are most commonly found in hotels, homeless shelters, and other overcrowded areas. 

Do Bed Bugs Cause Rashes?

Bed bug bites can be mistaken for allergic rashes, especially urticaria. Bites appear as itchy bumps on the skin in areas that were uncovered while sleeping. The rash may be grouped in a line, which shows the pattern of the insect feeding. Bumps tend to more red in the morning and fade as the day progresses.

Most people bitten by bed bugs assume they are experiencing an allergic reaction, but the reaction is typically due to the irritating nature of the bite, not an allergy.

While most people are not allergic to bed bugs, there are rare reports of anaphylaxis occurring as a result of bed bug bites.

What Can Be Done for Bed Bug Bites?

Physicians may misdiagnose bed bug bites as allergic reactions, and treat people with steroid pills, creams, or antihistamines. While antihistamines may decrease the itching associated with the insect bites, these medications will not make the rash go away.

Steroid creams, such as hydrocortisone (Cortaid, for example), can help the itch and rash resolve quickly.

Do Bed Bugs Cause Other Problems?

If you scratch your bed bug bite to the point where you break your skin, the bite may become infected. Infected bites can cause increased pain, redness or oozing at the site, and may get worse over time. If you think you have an infected bug bite, seek immediate medical attention.

Bed bugs may also be able to transmit the hepatitis B virus, which has been found in bedbug droppings, and the parasite Trypanosoma cruzi, which causes Chagas disease.

What Can I Do About Bed Bugs?

If you think you have bed bugs, call an exterminator and have them fumigate your home to get rid of any pests. Professional pest control companies can assist with the extermination process, usually with pesticide treatments. Sleeping in long-sleeved shirts, pants, and socks can help decrease the amount of skin available for the bugs to bite. You can also try using insect repellents containing DEET, as studies suggest it may prevent bites. 


Bed Bug Bites Often Misdiagnosed as Allergic Skin Rashes. Review of Allergy, Asthma and Immunology. March-April 2007:19.