HOW LONG DO BED BUG BITES LAST?

Written by: A O’Neill, Licensed Pest Control Technician

Bed bug bites typically take 2-3 weeks to fade if they are not scratched too much. Bites from this pest can cause different reactions in different people. Some may experience no reaction at all, others will develop mild swelling and itching, while a few may have a more severe allergic response causing the bites to take longer to heal.

What does a bite from a bed bug look like?

Bed bug bites look like a bite from a mosquito, flea, or other biting insect resulting in a small, red itchy bump (usually 2-5mm). Their bites are also easily mistaken for hives, given their small size.

Below are some images of bed bug bites. You can see how they can be mistaken for other insect bites or hives. See more pictures of bed bugs here.

Large welts on arm from bed bug bites
Bed bug bites on arm Credit: James Heilman, MD/CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)
Large red welts from bed bug bites on human back
Bed bug bites on back. James Heilman, MD/CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)
Large red welts from bed bug bites on persons back
picture of bed bug bites on back. J Heilman, MD/ CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)

Are these bed bug bites?

It’s hard to tell if the red marks on your body are bed bug bites unless you find these appleseed-shaped blood-sucking insects or signs of an infestation.

Even a GP cannot tell for certain if they are bed bug bites as they look similar to other insect bites.

However, some tell-tale signs increase the likelihood that they are, if:

  • You’ve recently traveled and stayed in a hotel that has bed bugs.

  • You’ve bought used furniture, such as a bed frame, box spring, or mattress. Buying used furniture is one of the ways you get bed bugs in the first place.

  • You’ve woken up to find red bumps on areas of your skin that weren’t there when you went to bed. Bite marks usually occur on areas of the body that are often exposed when sleeping, such as the face, back, shoulders, neck, arms, hands, and legs.
  • You find smeared blood or specks of blood on the bedsheets (which is bed bug excrement).
Bedbug bites on face
Bedbug bites on face
Credit: Original uploader Andybrookestar at English Wikipedia. [Public domain] https://commons.wikimedia.org/wiki/File:Bedbug_bites.jpg

Related: Identifying the early signs of bed bugs

Do bed bug bites itch and hurt?

Research studies found that your body’s immune system often does not react to the first bite because it hasn’t come into contact with the bed bug’s salivary proteins before. Therefore, reactions usually occur after repeated bites.[1]

A bed bug bite can cause an allergic reaction that results in urticaria (inflammation and swelling of the skin) at the bite site. So to begin with, you might notice a slight burning sensation followed by red welts appearing on your skin that usually become itchy.

People who react more severely often find the welts are painful and swollen. They can develop blood blisters, and intense itching is also common. As I said above, this can also happen when repeatedly bitten over some time. 

The most severe reactions to bed bug bites can include difficulty breathing, a swollen tongue, fever, and anemia. Thankfully, anaphylactic shock is extremely rare.

Why do bed bug bites itch so bad?

In order to feed on your blood, this pest uses a mouthpart (proboscis) with two stylets; one stylet withdraws your blood, and the other injects saliva containing an anticoagulant (blood thinner) and an anesthetic that numbs the bite site, so you don’t feel the bed bugs feeding.

As a result, your body’s immune system reacts to the allergens in the saliva and causes an allergic dermal response in the form of welts.

The bites start to itch once the anesthetic wears off because your body reacts to the saliva that was injected into the bite area.

Small red marks bed bugs bite reaction
Credit: Flickr.com louento.pix CC Licenses/by-nd/2.0/

How itchy are bed bug bites?

As mentioned, not everyone reacts at first; therefore, not everyone will find them itchy. 

Nevertheless, if you are hypersensitive to their bites the reactions will be more severe with severe itching and sore and inflamed welts.  According to studies, the itching seems to be worse in the morning, but again, this varies from person to person.[2]

How long do bed bug bites take to show up?

The symptoms of bites from this pest can start to show almost straight away. However, the initial reaction time can also range from a few hours to several days and even two weeks after the bite, which makes it hard to pinpoint exactly when and where the bite occurred.

Do the bites spread when scratched?

No, bed bug bites cannot spread when scratched because they are not contagious.  As we know, scratching can cause the bites to become infected, so it is best to avoid scratching them as much as you can – of course, that’s easier said than done!

Can you feel a bed bug bite?

Bed bugs feed on your blood at night when you’re asleep. However, they will come out to feed during the day if the infestation has grown large or if you sleep during the day.

As you’re asleep you won’t feel them piercing your skin to take a blood meal.  The injected anesthetic allows the bed bug to feed for up to 10 minutes uninterrupted. During that time, the bed bug can increase in length by up to 50%, and in weight by up to 200% as it fills itself up with your blood, as the photo below shows.[3]

Picture of adult bed bug before and after taking a blood meal
Picture of adult bed bug before and after feeding on a blood meal

Do bed bugs always bite in a line?

While it’s true that bedbug bites often appear in a straight line, this isn’t always the case as the images above show. You can be bitten on any part of the body that isn’t covered, and there can be a single bite, a line of bites, or clusters of bites. 

It is a myth that bed bugs bite in threes (breakfast-lunch-dinner), and there is no evidence suggesting that they do. 

A row with any number of bites is because bed bugs cannot bite through clothing or bedding, so they line up along the edge of a duvet or bed sheet where it meets your body and pierce your exposed skin to take a blood meal.  

Although bed bugs may sometimes probe your skin, they don’t want to be on you for any longer than they have to.  Most of the time, they just pierce you with their proboscis, gorge on your blood, and crawl off you, returning to their harborage sites immediately afterward.

Another explanation for a line of bites is the bed bug being disturbed when trying to feed. A bed bug feeds once in one night unless it is disturbed. If you suddenly move, it will withdraw its mouthpart and wait for you to be still again and reinsert it, usually close to where it was feeding. Hence the common idea that bed bugs always bite in a line.

Each probe and each reinsertion produces a bed bug bite, but finding a line of red bumps or welts should not be solely used as a way to diagnose bed bug bites.

What can I put on bed bug bites to stop the itching and heal them?

You might be tempted to scratch the bites, but don’t, as it may break the skin, causing bleeding or a secondary skin infection, such as cellulitis, which happens when bacteria enter the scratched area and cause an infection.

Scratching can also lead to scarring. A bed bug bite won’t leave a scar since its mouthpart is too small, but excessive scratching and skin breakage can.

Several over-the-counter (OTC) options are available which can help, such as:

  • Hydrocortisone cream to relieve itching and swelling.
  • Antihistamine cream or pill for itchiness.
  • Lotions such as aloe vera and calamine lotion can calm the redness and lessen the irritation.
  • Witch Hazel soothes the itching.
  • An ice pack wrapped in a towel and placed on the welts will help to reduce redness, swelling, and itchiness. A frozen bag of peas will work just as well as an ice pack.

Before applying any of the above, wash and dry the affected area thoroughly, and always get the advice of a medical professional to find out what is the best treatment option and how to use it.

Although the bites will heal over a couple of weeks, the bed bug infestation will grow, and you will continue to get more bites.

The physical symptoms of these pests feeding on you are bad enough, but some people find the long-term effects, and bed bug anxiety hard to deal with. And it’s not surprising as the thought of these pests crawling on you and biting you while you sleep is extremely distressing.

It’s vital then that as soon as you’ve identified that you have bed bugs, you act quickly to eliminate them and you can do this yourself if the infestation is in the early stages (this detailed guide will show you how to get rid of bed bugs permanently at home). 

However, it is always best to use a reputable pest control company to carry out an inspection, prepare a treatment plan and remove them for you.

Frequently asked questions

How can you tell the difference between bed bug bites and flea bites?

The bites from both insects look similar so it’s not easy to differentiate between flea and bed bug bites.  However, flea bites are often found on the lower legs and feet, while bed bug bites are typically on the upper body parts usually uncovered in bed, such as shoulders, face, neck, and arms

Are bed bug bites dangerous?

Bites from bed bugs can be dangerous for some people as they can cause a severe allergic reaction and harmful secondary infections such as cellulitis. However, the psychological impact of having bed bugs is also dangerous because of the distress, embarrassment, insomnia, and anxiety they cause.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3255965/

[2] https://www.researchgate.net

[3] https://jamanetwork.com/journals/jama/fullarticle/183643

I’ve been in the pest control industry helping people get rid of their unwanted pests for over 20 years, both in the UK and Canada.

As a licensed pest management professional, I’ve seen and treated just about every common household pest, insect, or rodent, you can think of. I’ve seen the damage caused when an infestation has been left too long and has become hard to get rid of.

For this reason, peststopsolutions.com was created. By having honest advice and the right guidance to hand, along with scientific evidence to back up claims, you are given information on the best eradication methods, as well as how to get rid of most pests yourself.