Bed Bug Bites Pictures

Pictures of bed bug bites and bed bug colonies

You may wonder what bed bug bites look like, especially if you suspect that may be the source of sores you developed overnight. Bed bugs have resurged and now can be found in many places. Like vampires, they like to live in dark places and feed on warm blood.

Bed bugs cause itching and swelling like mosquitoes. Unlike mosquitoes, bed bugs don't really spread infectious diseases, although they have been discovered infected with diseases from the humans they bite.

These bed bug bites pictures illustrate how bites can look, including photos from a researcher showing the immediate reaction, after 10 minutes, and after 24 hours.

Bed Bug Bites on Arm

Bed Bug Bites
(c) Claire Houck

Claire shared her photo of her mysterious sores. She went to the doctor to figure out what was happening and discovered that bed bugs had infested her New York City apartment.

Bed bug bite reactions are similar to mosquitoes. Bed bugs feed on blood and have a saliva that keeps blood from clotting so they can eat freely, just like mosquitoes. The two species aren't related, but like mosquitoes, the reaction from bed bug bites comes from an allergy to the saliva. Some reactions are very mild, while others can cause significant swelling.

The bite marks may be in a straight line, or they may have a random pattern. The bite marks can be found anywhere on your body.

Claire says the doctor diagnosed bed bug bites and prescribed an anti-itch cream. She didn't scratch the bites but noted that some of them scabbed over even without scratching.

Bed Bug Feeding Frenzy

bed bug bite reaction
(c) Lou Sorkin

Entomologist Lou Sorkin feeds his colony of bed bugs by letting them drink his blood through the little mesh top on their jar. He is quick to point out that given the opportunity, bed bugs would not bite in a cluster like this. When done this way, the bed bugs have a full-blown feeding frenzy, climbing over one another to get to the source of blood.

Sorkin says that the bed bugs would feed for a few seconds then move out of the way for a new wave of bed bugs to take over.

You likely won't feel bed bugs biting as they inject an anesthetic and anticoagulant when they bite.

Bed Bug Feeding Frenzy After 10 Minutes

bed bug bite reaction
(c) Lou Sorkin

Entomologist Lou Sorkin feeds his colony of bed bugs by letting them drink his blood through the little mesh top on their jar. Ten minutes after dinner, the area on his arm where the feeding frenzy happened is swollen.

Bed bug bite reactions come from human allergies to the bed bug saliva. Bed bug saliva serves a purpose similar to the saliva of mosquitoes, to thin the blood. This leads to swelling and itching for most people.

The CDC notes that bite marks can take as long as 14 days to show up for some people.

Bed Bug Bites After 1 Day

bed bug bite reaction
(c) Lou Sorkin

A day after letting several bed bugs feed on his arm through the screen at the top of their jar, entomologist Lou Sorkin shows the irritation reaction on his arm.

He says he doesn't experience much itching, but that is not the case for many people. Bed bug bite reactions are similar to mosquitoes: some people are very allergic while others have almost no reaction at all.


Parasites—Bed Bugs. Centers for Disease Control and Prevention. Updated May 24, 2016.