Lou’s bed bug bite photos

by nobugsonme on March 25, 2007 · 29 comments

in bed bug bites, bed bug research, bed bugs, photos

Before you look at Lou’s bite photos or read his description of them, I have to clarify, for those “newbites” who are unaware, that Lou Sorkin (American Museum of Natural History entomologist) keeps a bed bug colony so he can do research on them. Bed bug newsreels commonly feature one of a number of US entomologists feeding a lone bug. The idea that people do this voluntarily is surprising to people with bed bugs, but we are so lucky they do– because without more bed bug research, the future would be very bleak indeed.

I am adding these to the bite photos page, though they’re slightly unusual: they depict what happens when Lou feeds hundreds of bed bugs in one spot on his arm. Your bed bug bites won’t look like this.

However, I think Lou must be a lot less allergic to bed bugs than many of us to be able to withstand such a concentrated assault. We know that some Bedbuggers react quite badly (though not like this by any means) to even single bites, and hundreds in one spot could be quite harmful. At least one active member of our blog was rushed to the emergency room. Serious allergic reactions are rare, but the bed bug bite reaction is a histamine reaction to the substance the bed bug injects during feeding. Your level of allergic reaction may be worse or better than someone else’s. It might be worse or better depending on the size of the bug. It might be worse or better one day, or another. The truth is we don’t know enough about bed bug bites, yet.

The captions below each photo are what Lou added to the descriptions over at flickr.com.

dorsal view of arm, bed bug colony feeding

Lou says:

My arm after feeding a few minutes by the hundreds of bed bugs in the colony. Note individual welts when compared to other pictures in which the individual welts have coalesced into a large welt. After about 10 minutes of feeding, you cannot readily discern individual welts from individual bites.

top view forearm, close-up

Lou says:

About 10 minutes after having fed hundreds of bed bugs through the 1/3 mm mesh cover of colony container which is inverted on my arm during feeding. Since many crawl over one another during feeding frenzy, they produce the characteristic bed bug odor similar to a mixture of cilantro and citronella.

retromedial view forearm


10 minutes after feeding colony of bed bugs. Hundreds feed through 1/3 mm mesh holes at one time. Inflammatory reaction, but no itching to speak of. I experience a slight itchy feeling during feeding, but hundreds feeding at one time. When finished, they leave and others take their place.

dorsal  view of bite area


About 1 day after having fed bed bug colony. Note that swelling is appreciably down and pink diffuses out from central area. Bright red in area where feeding occured. This leaves in about a day, 2 days and skin back to normal level, just slightly darker than normal coloring for a week or so. Also not much itching to speak of: lucky for me. The itchiness can definitely vary from person to person.

I will link to this from the bite photos page, but I won’t put it all there, because Lou’s situation is a bit unusual and these bites aren’t really what most people should be looking for when they’re trying to diagnose their problem.

1 Bugalina March 25, 2007 at 10:02 pm

When I look at Lou’s bites I think they leave a very symmetrical mark…the nature of the symmetry could be helpful..for identification, maybe ??? Also, I want to tell Lou that he is doing such a tremendous public service in showing us his bite reactions…thank you Lou…Deb

2 nobugsonme March 25, 2007 at 10:36 pm

It looks symmetrical the next day, but not in the first photo…

3 Bugalina March 25, 2007 at 10:56 pm

nobugs…look at it…its almost perfectly round ???

4 nobugsonme March 25, 2007 at 11:02 pm

Okay, I see there’s an almost perfectly round outline on the first one too. I was looking at the parts that stuck out from that in the first one which are less pronounced later.

Were your bites symmetrical? I think the reaction Lou gets from 100 bugs feasting on one small area (which is not what everyone else experiences) might have a different effect.

5 Bugalina March 25, 2007 at 11:30 pm

My first bite was very raised and very round like a wheal, …all the bites following were flat puntures, two or three very round red marks…in a very perfectly straight row….occasionally I would get only one bite…the bites that were only one perfectly round mark were on my face and ear…the ones on my inner arm, stomach and ankles and legs were always two or three linear red round marks…but always very symmetrical…evenly placed and evenly round… the perfect roundness of the bites stands out in my mind…Deb

6 nobugsonme March 25, 2007 at 11:40 pm

Me: not very round, mostly more like pimples. And not in rows, sometimes triangles or single. Sometimes two right next to each other with one oddly shaped swelling. They look different on different people.

Thinking bed bug bites look like just one thing is why my own doctor sent me on a wild goose chase for months, when I had good reason to think I had bed bugs, and evidence. Hence I am wary of saying “they look like this” or “they look like that”, because our experiences are different. There are only two examples on our bed bug bites page (link at top), and they are very different. And they are just the tip of the iceberg–just myself alone, I have had multiple kinds even at the same time. And I never got the huge welts like Caryn or Caitlin.

I hope we can get more people to send in photos, for this reason!

7 Bugalina March 26, 2007 at 6:24 am

Yes…the photos are so good…I also think that the bites might differ from nymph to adult…

8 Paula March 26, 2007 at 7:16 am

I want to know why they are suddenly infesting everywhere again.
Is it just that travelling around the world is more accessible or is something to do with carbon dioxide levels.

Can someone help me understand why that practically became extinct even though people still travelled around the world in the 1970’s and 80’s?

9 Lou March 26, 2007 at 8:00 am

The reason for the “roundness” is due to the circular top of the container in which the bed bugs are kept. The top is a fine plankton net with 1/3mm holes. The bugs are concentrated in the approximately 1 inch circle plankton net while feeding (as the jar is inverted on my arm). Dermatologists who have seen the resulting “rash” diagnose the bites (bite area) as a contact dermatitis. This is understandable due to the “artificial circular area of bites” produced by hundreds of bugs feeding in the circle at one time. Normally, of course, bugs wouldn’t be concentrated in such as small area for feeding, but would be over a large area of a person’s skin and produce many feeding reactions in most cases. Remember that the lesion on my arm is around 2 inches across. All the individual bites have coalesced into one raised welt.

10 Bugalina March 26, 2007 at 9:13 am

Lou…I hate to ask you this because personally I couldn’t do what you are doing..but it would be better for the purpose of bite identification if you allowed only one to bite you in a spot..of course this would mean having to transfer a few….also…can you tell the difference between a male and female? And if you can, it would be interesting to separate them and see if their bites make a different reaction…Tnank you..Deb

11 S. March 26, 2007 at 10:02 am

Wow, Lou, thanks so much for sharing these. A hundred bugs at once just blows my mind.

My initial (and only) welt-like bite looked exactly like the final photo in this series. Dark, circular and angry. I wonder if it was from multiple bites, or just one?

12 Lou March 26, 2007 at 4:32 pm

I’m getting bites from adults and nymphs all at the same time — can’t differentiate during the feedings I do.

When I first had some bed bugs, I kept them in a container that could be opened and individuals taken out. Now all are in one jar, but I want to take some out, transfer to separate containers, and then I can work with individuals. Or if I receive bugs from another source, then I can start a new colony.
There’s another photo that I just uploaded that’s taken a few minutes after initial feeding, so individual welts can be seen.

13 Paula March 26, 2007 at 4:52 pm

I seem to be geting bitten all the time, but cannot see them. Is this a bedbug problem or I have I caught something else, perhaps fleas?

14 nobugsonme March 26, 2007 at 7:34 pm

Everyone–I just added the new photo Lou mentioned (which shows multiple marks just before they coalesce into one) as the first photo.

Paula–the spread is complicated and has been written about here many times. I don’t have time to do a FAQ on it today, but it seems to relate to several factors: 1/ DDT was outlawed in 1972, and was one of the main ways bed bugs were treated (though some say it was not effective against bed bugs by the time it was outlawed), 2/ PCOs (exterminators) used to spray baseboards of entire apts and homes for general pests. This stopped in the early 90s, and so bed bugs had time to come back. 3/ Lots of people blame increased travel and immigration; but we were traveling and immigrating in the 70s and 80s so i don’t find this convincing.

Paula, the question about fleas is answered in the general FAQs. please read the Frequently Asked Questions at top, and then post any subsequent questions click “Get advice” at top.

15 James Buggles April 6, 2007 at 7:36 pm

For identification purposes, this is the best photo I’ve found because it drives home their actual size. Most photos on the Web are blown up to the point of not being helpful. Perhaps you can obtain permission to add this photo to the site.

16 Bbbeverly April 24, 2007 at 4:59 am

II i want to no the best treat it yourself chemical for bedbugs or chinches there is because i can not afford to have a pest control come in and do it for me.Although, i did call orkin pest control they said it would cost me 585.00 for one treatment!!! I am on social security and disability i cannot afford that please help!

17 wantmyskinback April 24, 2007 at 8:06 am

If you call the Health Department in your city, you might be able to obtain assistance.

18 nobugsonme April 24, 2007 at 12:13 pm


Do you rent your home?
In most places in the US, your landlord must pay for professional treatment. If done right, it is much safer and more effective. Click FAQs above and read the FAQ for tenants.

19 Lou July 14, 2007 at 6:31 pm

James, the photo you are linking to depicts bed bug nymphs and not adults, so these bugs are less than 4 or 5mm long (less than 1/4 inch long). The close up is of a nymph. Not sure which instar, could be first or 2nd instar.

20 maria santos April 14, 2008 at 5:38 pm

i dont know about this type of bug but since i moved to this new home my husband has been biten several times and he is in really bad shape they bite him on his head and all over the body and he has a lot of swelling on this bites i also am getting bites but no itch or swelling just red bloches im consere about my husband is thier something we can do we are treating the home and even throw out our bed what more can be done

21 nobugsonme April 14, 2008 at 5:42 pm

Maria, I would not throw out your bed. Click the link above to “How to Get Rid of Bed Bugs (FAQS)” and read them carefully. Start with the basics at the top. Go to the forums (link above) if you want more advice from others.

22 Sergio "G" April 14, 2008 at 9:38 pm

Dear sir may curiosity lay in the colony for example :
let say that you bring one of this criters home, is one able to reproduce into many.
How bout if is a male or a female it made any different .
What a mean is in some insect the gender dont matter to multiply, It”s this the case ?.
I live in a apartment and also want to know if they can travel for one apparment to the next ?
It”s may balive that if you can interruct the reproductive cyclel in this criatures you can control the festation .
I have question like how the male and female found each others if is by sent or by a particular call. And if that is the case blocking that sent would be afect way to
keep then at part and prevent a full blown colony .
Hopeing to get some answers fron you
Trully your Sergio “G”

23 nobugsonme April 14, 2008 at 11:28 pm

I suggest starting here for an introduction to bed bug reproduction.

And yes, they can go from apartment to apartment–in any direction including up, down, all sides. Get immediate professional help, and read our FAQs for more information:

24 Sergio "G" April 15, 2008 at 6:13 pm

Dear nobugssonme :
I read the page that your suggest and is very informative but i been doing some research of my own and i found that the male in some cases have in the sperm
a agen that kill the sperm of other male that coupulate with the same female in oder to maintain his genes (Couser the result of this is that the life of the female is shorted ) My question in all of this is this antibouties are the answer to eliminate this
vermint from our life ?

25 maria santos April 15, 2008 at 6:20 pm

dear nobugsonme i would like to thank you for your reponce to my question and i have done a lot of research about theses bugs but one thing for sure i found one way to kill them where i find them i’ve become dirty harry armed and dangerous with my hair blower i’ve kill on contack and i feel good about it and we got a professional to handle the rest but i did my pillows and mattress and bang dead i wanted to share with you and im carefull i wont burn my house down but a lady can arm herself with a blower leave just a little vent of the pillow case and dead duck

26 hopelessnomo April 15, 2008 at 7:56 pm

Hi Sergio,

I suspect your questions are for Lou, but he may not check this thread.

Sounds like you are interested in the research on this topic. Luckily for you, this is an area where there is actually ongoing research. A couple of papers are available online. See this and this.

One can hope that these inquiries may eventually lead to new insights valuable for pest control. From my limited awareness of the subject, it seems that is an expressly stated goal of the researchers involved.

In the short term, however… sexual conflict in bedbugs is plenty fascinating, but the state of knowledge will not quite get you a decent night’s rest. Yet.

In any case, good luck.

27 Viktoria September 8, 2008 at 9:52 am

I have been experiencing itching bites on my elbows that I would notice in the morning. Last night I went to sleep in my bed wearing a sweater that covered up my elbows, and instead woke up with bites on my wrist. They seemed similar to mosquito bites because they were very itchy, but I didnt understand why they only liked my elbow and my wrist. My children have bites on their legs and all over their bodies, they looked like mosquito bites that made them have extremly bad allergic reaction. My 4 yr old son wont even sleep in his bed, he sleeps on the floor in his room. I am starting to think I may have bed bugs in my house. I have gone from thinking they were a rash to mosquito bites, to spider bites to bed bug bites. Could you tell me if this sounds like I have bed bugs? Thanks so much..

28 nobugsonme September 8, 2008 at 10:02 am

It sounds probable. You need a careful inspection, preferably by a pro who knows bed bugs. Don’t start cleaning or throwing things away. They need to see the place as is. You can also learn to inspect from some of the resources in the LINKS page, but if you do this and confirm their presence, I seriously recommend getting someone experienced to do an inspection of their own and treat your home.

29 NOTOBUGS May 27, 2009 at 1:33 am

I just recently bought a new apartment on the 2rd floor of a new building. No one had occupied the apartment before – it wasn’t a resell apartment. Before moving compleltely into the apartment (I had only moved a few suitcases as my shipment just arrived today) , I found out that someone on the 7th floor had discovered bed bugs. – I am on the 2rd floor with a corner apartment and my wall are shared with the stairwell on one side and the hallway and elevator on the other side. I don’t share any adjacent walls and I believe the apartment above me is empty and below me is the management company offices. I have been told by the management company that the person in the 7th floor apartment has hired a PCO and began treatment.

I wanted to make sure that my apartment was bed bug free as I had been freaking out about them since reading an article on Yahoo a couple weeks ago and then knowing there was an ifestation in the same building has caused me lots of lost sleep. Last Thursday, the PCO came which included the K9. He told me that there are “No signs of activity”. What a big relief that was until yesterday my knee was hurting – it felt like a bruise but was actually red – like a light red rash. Today, my calf hurts (feels like I had a Charley Horse) – really, it feels like a painful bruise like I had really hit my knee and calf on something although it’s not a bruise, it’s a bit of a red rash. Even hurt when I walked and put pressure on it. Now, I am freaked out again – – could this be caused from bed bugs? I have spent my entire two weeks reading the Internet about those things and their bites – not once did I see anyone complain about pain (it feels like muscle pain). No itching – (just the psychological whole body itch for the last two weeks.) Or could these be some other kind of bites?

I have looked and looked and haven’t found anything on the sheets or around the bed room area or the rest of the apartment for that matter. I put my matress and pillows are in encasements and on a metal bedframe as I am still waiting for the bedframe to be delivered (it was out of stock).

I did find a Spider Beatle in the microwave which was the reason that I called for and scheduled an inspection by the PCO last Friday. Do they bite?

I will now call the PCO and set-up an appointment for them to come back and do a comprehensive inscpection again including the K9.

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