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Bed bugs: Signs and symptoms

What are the signs of bed bugs?

Having bite marks on your body is the most common sign of bed bugs. Most people are bitten while they sleep and do not know that they have been bitten until the next day when they notice one or more of the following:

  • Several welts, often appearing in a line that zigzags

  • Welts that itch intensely

  • Specks of blood on the bedding

Bed bug bites

The bites often appear in a zigzag pattern as shown here.

Bed bug bites often appear in a zigzag pattern

The first time you are bitten, the bites may not itch right away. It can take time for your body to develop a reaction to the bites. Some people develop itchy welts within a few days of the first bites, but it can take as long as 14 days before the bites itch.

People tend to become increasingly sensitive to bedbug bites. If you have a bedbug infestation and the bugs bite repeatedly, you may get itchy welts within seconds.

You will not see bed bugs living on your body. Unlike lice and the mites that cause scabies, bed bugs do not live on humans. Bed bugs come out of hiding to feed on human blood. Feeding lasts about 4 to 12 minutes. After a bed bug feeds, it returns to its hiding place.

Serious and life-threatening reactions to bed bug bites

Although less common, it is possible to develop a serious or even life-threatening reaction to bed bug bites. These reactions include:

  • Breathing is difficult

  • Heartbeat is irregular or forceful

  • Tongue swollen

  • Blisters, especially large blisters

  • Fever

  • Feeling very sick

  • Infection from scratching

  • Anemia (rare, but can develop when a person gets numerous bed bug bites)

Serious reactions require immediate medical care.

Getty Images

Steen CJ, Carbonaro PA, Schwartz RA. “Arthropods in dermatology.” J Am Acad Dermatol 2004; 50:819-42.