How Are Bed Bug Bites Diagnosis

How are bedbug bites diagnosed?

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Confirming the diagnosis of a bedbug bite sometimes is difficult. Obtain a detailed history of the home environment, work conditions, and presence of domestic animals.

Also consider papular urticaria, [28] and watch for and treat any secondary bacterial infection. Transmission of trypanosomiasis or hepatitis B is possible and might be considered in appropriate settings.

Targetoid or edematous plaques may require distinction form erythema multiforme and Sweet syndrome. [27]

Related Questions:


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Bed bugs: Diagnosis and treatment

How do you know if you have bed bugs?

To find out if you have bed bugs, you need to look for two things:

Bites on your body

Signs of bed bugs

Bites on your body:If you have bed bugs, you’re likely to have bites. Bed bug bites usually cause itchy welts. These welts usually appear in a zigzag pattern as show in the photo below.

Bed bug bites

When bedbugs bite, you often see clusters of bites. Each cluster usually contains 3 to 5 bites that appear in a zigzag pattern.

You’ll seldom see bed bugs, so many people mistakenly believe that mosquitoes, fleas, or spiders bit them. Sometimes people mistake bed bug bites for a common skin condition such as an itchy rash, hives, or chickenpox.

To make sure you have bed bugs, you’ll need to look for signs of bed bugs.

How to check for bed bugs

Although bed bugs don’t usually require serious medical attention, they can cause a great deal of anxiety and restless nights. To help find bed bugs before they find you (and your belongings), dermatologists recommend looking for the following signs near places where you sleep.

How to check for bed bugs

Although bed bugs don’t usually require serious medical attention, they can cause a great deal of anxiety and restless nights. To help find bed bugs before they find you (and your belongings), dermatologists recommend looking for the following signs near places where you sleep.

Signs of bed bugs:This step is important. If you have a bed bug infestation, you need to find out so that you can get rid of the bed bugs. Getting rid of the bed bugs is the only way to stop the bites.

If you have a large number of bed bugs, you may see the bugs. Most people, however, only see signs of bed bugs. To look for signs of bed bugs, check the places that people sleep for the following:

A sweet, musty odor.Take a deep breath. If you notice a sweet, musty in your hotel room, cruise-ship cabin, or other sleeping area, there may be a heavy bed bug infestation in the room. Bed bugs produce chemicals to help them communicate, although not everyone will notice the smell.

Specks of blood on bedding, mattresses, or upholstered furniture such as couches and headboards.Look carefully at your blankets, sheets, and mattress pads and then check the mattress and box spring. Are there specks of blood anywhere, especially near the seams? If so, there could be a bed bug infestation. You should also check for specks of blood on all upholstered furniture, including couches and headboards.

Exoskeletons.Bed bugs have an outer shell that they shed and leave behind. Do you see shell-like remains on the mattress, mattress pad, or beneath couch cushions?

Tiny, blackish specks.If you see blackish specks on the bedding, mattress, headboard, or beneath couch cushions, it could be bed bug excrement.

Eggs.After mating, female bed bugs lay white, oval eggs in cracks and crevices. Keep in mind that these will be small, as a bed bug is only about the size of an apple seed. The photo below shows a bed bug near eggs. The photo was magnified so that you can see the bed bug and eggs.

If you do get bed bugs and have many bites or a bite that looks infected, see a board-certified dermatologist. A dermatologist can treat an infection and help relieve the itch.

Bed bug with eggs

A bed bug is a tiny insect with a broad, oval body. If it has recently eaten, it has a reddish-brown color.

If you see bed bugs, they will likely scurry toward the closest hiding place. Any dark place such as inside a mattress or even a picture frame makes a good hiding place.

As you watch bed bugs move, it can look like they are flying or jumping because they can crawl quickly. Bed bugs cannot fly or jump; they can only crawl.

If you find signs of bed bugs, call a pest-control company or your property manager. You should not use bug spray or a fogger. These products have little effect on bed bugs.

Treating bed bug bites

You should see a dermatologist for treatment if you have:

Skin infection (bites feel tender or ooze discharge, such as pus)

An allergic skin reaction (skin red and swollen or hives)

Your dermatologist may prescribe the following to treat bed bug bites:

Allergic reaction.Some people may require an injection of an antihistamine, corticosteroid, or epinephrine (adrenaline) for a severe allergic reaction.

Infection.An infection may require an antibiotic. If the infection is mild, your dermatologist may recommend an antiseptic medication that you can buy without a prescription. Your dermatologist will tell you which one to use. Your dermatologist also may recommend an antiseptic to prevent a skin infection.

Itch.A prescription antihistamine pill or liquid can help. You also can apply a corticosteroid to the bites. Your dermatologist will tell you which is best for you.

At-home treatment

If you do not have any signs of an infection or a serious reaction, you can often treat the bites at home.

To treat bed bug bites:

Wash the bites with soap and water.This will help prevent a skin infection and help reduce itchiness.

If the bites itch, apply a corticosteroid cream to the bites.You can get a weak form of this medicine without a prescription at your local drugstore. Stronger corticosteroids require a prescription.

Bed bug bites usually heal and go away within a week or two.

Getty Images

Leverkus Met al. “Bullous Allergic Hypersensitivity to Bed bug Bites Mediated by IgE against Salivary Nitrophorin."J of Invest Dermatol. 2006;126:2364-2366.

Liebold Ket al. “Disseminated bullous eruption with systemic reaction caused by Cimex lectularius.”J Euro Acad of Dermat and Vener. 2003;17:461-463.

Steen CJ, Carbonaro PA, Schwartz RA. “Arthropods in dermatology.”J Am Acad Dermatol2004; 50:819-42.

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Bed Bugs FAQs

What are bed bugs?

Bed bugs (Cimex lectularius) are small, flat, parasitic insects that feed solely on the blood of people and animals while they sleep. Bed bugs are reddish-brown in color, wingless, range from 1mm to 7mm (roughly the size of Lincoln’s head on a penny), and can live several months without a blood meal.

Where are bed bugs found?

Bed bugs are found across the globe from North and South America, to Africa, Asia and Europe. Although the presence of bed bugs has traditionally been seen as a problem in developing countries, it has recently been spreading rapidly in parts of the United States, Canada, the United Kingdom, and other parts of Europe. Bed bugs have been found in five-star hotels and resorts and their presence is not determined by the cleanliness of the living conditions where they are found.

Bed bug infestations usually occur around or near the areas where people sleep. These areas include apartments, shelters, rooming houses, hotels, cruise ships, buses, trains, and dorm rooms. They hide during the day in places such as seams of mattresses, box springs, bed frames, headboards, dresser tables, inside cracks or crevices, behind wallpaper, or any other clutter or objects around a bed. Bed bugs have been shown to be able to travel over 100 feet in a night but tend to live within 8 feet of where people sleep.

Do bed bugs spread disease?

Bed bugs are not known to spread disease. Bed bugs can be an annoyance because their presence may cause itching and loss of sleep. Sometimes the itching can lead to excessive scratching that can sometimes increase the chance of a secondary skin infection.

What health risks do bed bugs pose?

A bed bug bite affects each person differently. Bite responses can range from an absence of any physical signs of the bite, to a small bite mark, to a serious allergic reaction. Bed bugs are not considered to be dangerous; however, an allergic reaction to several bites may need medical attention.

What are the signs and symptoms of a bed bug infestation?

One of the easiest ways to identify a bed bug infestation is by the tell-tale bite marks on the face, neck, arms, hands, or any other body parts while sleeping. However, these bite marks may take as long as 14 days to develop in some people so it is important to look for other clues when determining if bed bugs have infested an area. These signs include:

  • the bed bugs’ exoskeletons after molting,
  • bed bugs in the fold of mattresses and sheets,
  • rusty–colored blood spots due to their blood-filled fecal material that they excrete on the mattress or nearby furniture, and
  • a sweet musty odor.

How do I know if I’ve been bitten by a bed bug?

It is hard to tell if you’ve been bitten by a bed bug unless you find bed bugs or signs of infestation. When bed bugs bite, they inject an anesthetic and an anticoagulant that prevents a person from realizing they are being bitten. Most people do not realize they have been bitten until bite marks appear anywhere from one to several days after the initial bite. The bite marks are similar to that of a mosquito or a flea — a slightly swollen and red area that may itch and be irritating. The bite marks may be random or appear in a straight line. Other symptoms of bed bug bites include insomnia, anxiety, and skin problems that arise from profuse scratching of the bites.

Because bed bug bites affect everyone differently, some people may have no reaction and will not develop bite marks or any other visible signs of being bitten. Other people may be allergic to the bed bugs and can react adversely to the bites. These allergic symptoms can include enlarged bite marks, painful swellings at the bite site, and, on rare occasions, anaphylaxis.

How did I get bed bugs?

Bed bugs are experts at hiding. Their slim flat bodies allow them to fit into the smallest of spaces and stay there for long periods of time, even without a blood meal. Bed bugs are usually transported from place to place as people travel. The bed bugs travel in the seams and folds of luggage, overnight bags, folded clothes, bedding, furniture, and anywhere else where they can hide. Most people do not realize they are transporting stow-away bed bugs as they travel from location to location, infecting areas as they travel.

Who is at risk for getting bed bugs?

Everyone is at risk for getting bed bugs when visiting an infected area. However, anyone who travels frequently and shares living and sleeping quarters where other people have previously slept has a higher risk of being bitten and or spreading a bed bug infestation.

How are bed bugs treated and prevented?

Bed bug bites usually do not pose a serious medical threat. The best way to treat a bite is to avoid scratching the area and apply antiseptic creams or lotions and take an antihistamine. Bed bug infestations are commonly treated by insecticide spraying. If you suspect that you have an infestation, contact your landlord or professional pest control company that is experienced with treating bed bugs. The best way to prevent bed bugs is regular inspection for the signs of an infestation.

This information is not meant to be used for self-diagnosis or as a substitute for consultation with a health care provider. If you have any questions about the parasites described above or think that you may have a parasitic infection, consult a health care provider.

How Bedbugs Are Diagnosed

Rod Brouhard is an emergency medical technician paramedic (EMT-P), journalist, educator, and advocate for emergency medical service providers and patients.

Casey Gallagher, MD, is board-certified in dermatology and works as a practicing dermatologist and clinical professor.

Bedbugs are diagnosed in two ways. The first is the appearance of bites on your body. However, these are very similar to other insect bites and can appear days after being bitten. Finding the signs of bedbugs in your sleeping environment is more conclusive evidence that there is an infestation. You will usually do your own self-diagnosis, but you might see a doctor due to unexplained bite marks or a skin infection after scratching. Learn how to determine whether you have been bitten by bedbugs.

Self-Checks/At-Home Testing

It is difficult to tell bedbug bites from those of mosquitoes, fleas, or other insects. You likely won’t feel bedbugs biting as they inject an anesthetic and anticoagulant when they bite. You may develop bite marks one to 14 days after being bitten.   As with mosquitoes, their saliva can provoke an allergic reaction at the site of the bite. Some people have no reaction, others have a mild one, while some can have significant swelling.

A typical reaction the first time you are bitten is a red, itchy bump, and you may see a central blood dot. When you have repeated bites, your body may react in different ways and the bites can form wheals or blisters.

The bite marks may be in a straight line, cluster, or a random pattern. One classic pattern is three bites in a line—breakfast, lunch, and dinner. Bed bugs are not picky eaters when it comes to location—any exposed skin will do—but they won’t necessarily go farther than they have to. Expect to see bites more often on the face, hands, and feet.

This photo contains content that some people may find graphic or disturbing.

Environmental Checks

The only way to know for sure if your symptoms are, in fact, a result of bed bugs, is to find the bed bug infestation in your room or furniture.  

You can check bedding, mattresses, furniture, and crevices in walls for bed bug infestation. Do your inspection just before dawn, which is when they are the most active. The bugs will be larger and slower after feeding. Bedbugs will quickly flee from light, so live bugs are best located in the folds and seams of mattresses and sheets. Bedbugs are about the size of an apple seed, about 1/4 inch long. They change from light brown to purple-red after feeding. You may also see their eggs, which are about the same size as the adults. The eggs will often be in seams, cracks, or crevices.

You are more likely to find their molted exoskeletons and dark specks of their feces. Also look for rust-colored blood spots on bedding and mattresses, which can come from the blood in their feces or from having crushed a bedbug who was feeding. A room with a heavy bedbug infestation might have a sweet, musty odor.

Differential Diagnoses

Most of the time you won’t go to a doctor for bedbug bites. However, the bites can mimic other rashes or you might develop a skin infection from scratching, and those factors may send you to the doctor.

Be prepared with a timeline of your symptoms. You should note any travel you have done, any new furniture, bedding, or mattresses, and a list of your medications and supplements. Bring photos of any suspicious specks found on your bedding or furniture.

Your doctor will perform a physical exam and take your medical history. This is usually enough to make the diagnosis or rule out other causes.

Some diagnoses your doctor will consider due to your bite reactions include:

  • Mosquito, flea, chigger, tick, or spider bites: These can look very similar in appearance to bedbug bites and it may not be possible for a doctor to tell the difference.
  • Scabies: This is a parasitic mite that is spread by skin-to-skin contact. It lays eggs under the skin and an itchy rash develops when the larva hatch.
  • Lice: Body lice and head lice can lead to scratching, with inflamed or infected scratch marks.
  • Antibiotic reaction
  • Eczema
  • Fungal skin infection
  • Hives
  • Food allergy
  • Chickenpox

Environmental Diagnosis of Bedbug Infestation

If you are unsure whether what you find are traces of bedbugs, the National Pesticide Information Center lets you search for local resources that can help with identification of photos or samples you collect.   You may want to enlist a professional pest control expert to determine whether or not you have bedbugs in your home and what rooms might be infested.

How do I diagnose a bed bug bite?

Bed bug bites are simple to diagnose as long as you know what to look for. Confirming that the bites are from bed bugs is the first step in your treatment process; once you’re sure that you are being bitten by bed bugs, you’ll want to get started with our 4-step solution right away.

Appearance:Bed bug bites are round, red, and bump up from the skin. They look very similar to mosquito bites, and the two bites are commonly mixed up. The center of the bites are often a darker shade of red, and are about the size of a ballpoint pen tip.

Placement:Bed bug bites generally appear as lines or clusters. The most common grouping is what experts refer to as a “breakfast, lunch, and dinner” cluster; this is caused by bed bugs feeding for a few minutes, then moving to another spot before returning to their nest. Bites appear on exposed skin, like the arms and underarms, neck, and face.

Reaction:The bite itself will usually be painless, as bed bug saliva contains chemicals that numb the skin and prevent blood clotting. Reactions to the bites differ from person to person – some don’t react at all, while others experience severe itching or blistering.

Treatment:Usually, no treatment of the bites is required. If you experience severe itching, try applying a corticosteroid cream, or taking an antihistamine. Bacterial infections can occur after heavy scratching, and may require antibiotics. Consult your dermatologist for the best recommendations for your needs.

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