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How to Spot Bed Bug Symptoms and Signs

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Bed bug bites and related symptoms vary from person to person. Since bites are indistinguishable from the bites of other insects, the only way to determine the cause is to confirm with other signs such as fecal stains on your mattress.  

Bed bug bites are an allergic reaction and are commonly seen in individuals that are allergic or suffer from urticaria, which are inflamed, swollen red areas at each location where a bite took place (it is a single skin puncture, not a bite). Over 50% of people show no skin reaction. This does not mean that they were not bitten. It just means they are not allergic to the bites.

The bites range in size (2mm to 5mm) and are maculopapular in most people (small, circumscribed, usually discolored slightly raised spots on the skin.)

How Long For Bed Bug Symptoms to Appear?

Symptoms can appear in minutes to hours to two weeks. Bed bugs usually bite exposed skin and sometimes under loose clothes. They tend not to bite the bottom of the feet. 

4 bed bug skin bite examplesBed Bug Bites Vary By Person and Allergic Response. A Small Hard to See White Pin Spot at the Center Is Where the Insect Inserted a Stylet to Withdraw Blood

Bite Symptoms with Puss

In highly allergic people, the reactions can include urticaria (slightly elevated patches or wheals) that are redder than any surrounding skin or a bullous rash (pus-filled bumps that are larger than 5mm) and skin blisters.

Bed bug bite symptoms  vary between people. In terms of skin-related symptoms such as bites, most people show no skin reaction, particularly the elderly due to a slower metabolism.

Itch is the other major skin related symptom. Avoid itching the spots, since this can introduce infection. In most allergic people, symptoms appear within an hour. Others can have a reaction which is delayed several days after being bitten. After symptoms appear, the problem should resolve  itself without any treatment in 3 to 5 days.

Other bed bug signs include mattress stains and finding and identifying the bed bugs themselves.

Pictures showing bed bug mattress stains and bite symptomsBed Bug Signs and Symptoms Include Bites on the Arm,
Stains on a Mattress or Capturing an Insect for Identification

Tips on How to Spot Bed Bug Signs

A skin reaction alone is not enough to determine if you have a bed bug problem as bites can be caused by other insects and factors such as an allergy to food or something in the environment. Because of this, its important to confirm any suspicion of bed bugs with other signs such as  fecal markings on the bed.

As shown in these pictures of bed bug signs, a combination of bed bug bite reactions and other proof such as fecal marks or even capturing a live insect for identification are needed.  Note how in these pictures bed bug symptoms such as bites vary between people.

Bed Bug Stains at Edge or Carpet or on Mattress Confirm The Presence of an Infestation

Bed Bugs Symptoms, Causes and Treatments

The most common bed bug symptoms are small red bumps or welts that resemble mosquito bites.  There are often multiple bites in one area and they are sometimes formed in rows. The rows are due to resting an arm on a mattress seam or other area where the insects are hiding.

Bites can occur on any area of the body.  They are not bites, but a single skin puncture in the center of the skin lesion that forms. This is why some bites have a small white center, surrounded by a red area. 

Bed bug symptoms are caused by an allergic reaction. When bed bugs bite, they secrete a chemical that prevents blood from clotting. This chemical also numbs the area, so you may not feel the big biting you. Many people are allergic to this chemical. If you have a skin reaction to bed bug bites, you’re one of them. The more severe the allergy, the more severe the symptoms.  Symptoms can also worsen with each subsequent biting episode.

Symptoms also include itching, which can sometimes be severe. The itching can keep you up at night. It’s important not to scratch the bites, though, regardless of how much they itch as this can introduce infection.

In rare cases, bed bug bites may cause large reddened areas or hives, up to eight inches across. They may also cause blisters or pus-filled sacs.

You should know, though, that bed bugs do not spread disease. Therefore, bites are rarely dangerous.

Allergic reactions are the worst symptoms of bed bugs caused by the bites. It is possible that the allergic reaction can cause welts on the skin or hives, even hives that are 8 inches wide. You may also see blisters and puss.

In people that are extremely allergic to the bites, they can cause a problem called an anaphylactic shock, which is a sharp drop in blood pressure accompanied by breathing problems.

The majority of people, estimated to be 50% to 70% will show no skin reaction.  This does not mean that they have not been bitten; it just means that they are not allergic to the bites.

Pictures of bed bug symptoms

Bedbug Bites are an allergic reaction and will vary between people.  Most people will have a minor skin reaction as shown below.  Bite reactions can vary between episodes, so if you are bitten again next year, you could see a different bite reaction.

Small skin reactions is referred to as urticaria, which means skin inflammation and swelling at every bite location. 

Picture of Bed Bug Bites on Arm
Source: Mayo Foundation
bed bug bites on armMild Bed Bug Bites on Arm
A More Severe Bed Bug Symptom is a Wheal or Round Skin Reaction that Forms on Some Individuals

In individuals that are very sensitive to bed bug bites, they will see a more pronounced skin reaction which are referred to as being bullous (fluid or puss filled bump). 

bed bug puss filled bites on stomachBed Bug Bites on Abdomen. Strong Allergic Reactions include Pus Filled Bites
Bed Bug Symptoms on the Legs or Arms Might Be in a Straight Line, Indicating that This Body Part Was Resting along a Bed Seam or Hiding Place

In highly allergic people, bed bug symptoms can include skin blisters. 

Bed Bug Bite Blisters on ArmBed Bug Bite Blisters on Arm

In very rare cases allergic individuals can have an asthmatic reaction or suffer from a condition called anaphylaxis, which is an allergic reaction causing breathing problems, a lowering of the blood pressure and shock.

treating bedbug Symptoms

Bed bug bites rarely require medical attention. Occasionally they might get infected, in which case you should see a doctor. Don’t scratch the bites, because that can break the skin and increase the risk of infection. If the bites do become infected, you’ll need antibiotics.

Wash the area with the bites with an antiseptic soap (most soaps these days are antiseptic, but read the package to find out) to help prevent infection.

If your bites are very itchy, you can use calamine lotion or another over-the-counter cream to treat insect bites and stop itching. Some people also take an antihistamine like Benadryl to control the allergic reaction.   You can also purchase products that are made specifically for bed bug itch.

There is also a prescription medication that can help with the itching, but usually over-the-counter remedies do the trick.

If your bed bug symptoms are severe, for instance, if you have the blisters or pus-filled sacs, you should see your doctor. Make sure you share your suspicion of bed bugs with your doctor. You should also see your doctor if you think your bites have become infected. Your doctor can tell you if there is any treatment recommended for your case of bed bug bites.

preventing bed bug symptoms

Bed bugs rarely bite skin areas exposed when sleeping. Wear tight fitting clothes to bed and this will reduce the number of bites.  Other precautions include:

  • Move the bed at least 6 inches from the wall and all furniture.  Wash all blankets and linen in hot water followed by 20 to 30 minutes in the dryer.  Vacuum all bed seams.  Use a mattress safe spray such as Sterifab on the mattress, box spring and bed frame. 
  • Place double sided tape around each bed leg. Consider adding a bed bug trap under each leg.

These are only temporary measures. We always recommend hiring a professional, experienced exterminator.  Start by calling Home Advisor. You can also call 1.877.673.2704. 

An exterminator should provide a free in-home visit and free quote. 

If you decide to treat the home yourself, be sure to buy a bed bug kit that contains the combination of products needed to do the job right.

how to spot bed bug signs when traveling

Also, be sure to learn how to spot signs of bed bugs when traveling.  Before bringing luggage into the hotel room, check the mattress for fecal stains and look behind the headboard as this is the best way to detect bed bugs in any room.  For the most part, a clean mattress means a clean room.  Another precaution is to spray your luggage before packing with a product such as JT Eaton Luggage spray, which will provide 3 to 6 weeks of protection.  Keep your luggage zipped when not in use and keep it elevated and away from any walls.  Never unpack luggage in a hotel room and the furniture could be infested.  You can also ask if the room you are staying in or any adjacent rooms have been treated for bed bugs.

killing bed bugs in your home

If you find that you do have bed bugs, be sure to act quickly on your  bed bug treatment plan. Killing bed bugs fast before they start to multiply will make sure that you and your family will be free of bed bug symptoms in no time.

One approach is to bring in an exterminator from a reputable company that provides free quotes such as Home Advisor (866-214-8380). The exterminator can confirm that you actually have bed  bugs and outline a plan of attack. It often takes three treatments from a professional before the bed  bugs are gone.

other insects

If bites are the only sign of bed bugs, and if the temperature is over 60F, then any bites may not be bed bugs. In this case, mosquitoes are a more likely cause of any problem. Other possible causes include:

  • Lice
  • Ticks
  • Fleas
  • Bird and Rodent Mites
  • Scabies
  • Spiders


Review these brochures for more information on how to recognize and treat bed bug symptoms.

How to recognize bed bug bites. Review of other possible causes.
Available in a free Ebook

A Comprehensive guide to identifying bed bugs, bed bug bites and prevention tips.
Available in a free Ebook

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