Bedbugs: How to Know, and What to Do First

TL;DR: Bedbugs do not carry disease. They are miserable to live with, and they are not a danger to your health. The bites cannot tell you whether you have them, because some people never react at all and lots of other things leave the same marks. To know, you have to find the bugs or their droppings, which look like small dark ink dots along the mattress seams, the box spring, and the bed frame. Take a flashlight and look after dark. If you find them, call a pest control company. Do not spray anything yourself and do not throw out your mattress; both of those spread the bugs and cost you money for nothing. Zip the mattress into a bedbug cover and leave it zipped. Put bedding and clothes in a hot dryer for 30 minutes, and skip the wash. If you rent in Philadelphia, tell your landlord in writing today, because the city gives you protection and writing it down is what starts the clock. Call a doctor if a bite turns hot, swollen, or starts draining, or if you have stopped sleeping.

Almost everyone who raises this with me apologizes first. They lower their voice, or they explain how often they vacuum, or they tell me they have no idea how this happened. So before anything else: bedbugs have nothing to do with housekeeping. They feed on people, they travel in luggage and secondhand furniture and along the inside of a shared wall, and a spotless house in a well-kept building is as good a target as any. The shame is the part I would put down first, because it is the thing that keeps people from telling anyone for weeks while the problem gets bigger.

Can you tell bedbugs from the bites?

No, and this is the single most useful thing to know before you tear your bedroom apart. A bedbug bite has no appearance that belongs to it alone. What shows up on skin is your immune reaction, and that reaction varies enormously from person to person: some people develop itchy welts, some develop almost nothing, and a substantial number never react visibly at all, which is why one person in a bed can be covered in marks while their partner sleeps beside them untouched and uninfested in appearance only.¹

Timing muddies it further. The first time you are bitten, the reaction can take days to appear. After repeated exposure the same bite starts showing up within hours, so the pattern you are seeing this week may say more about how long this has been going on than about what bit you.

You may have read that bedbug bites come in a line of 3, sometimes called breakfast, lunch, and dinner. Rows do happen, and they happen with other insects too, and plenty of bedbug bites arrive scattered, so a row is a hint to keep looking.

What settles the question is physical evidence, and there are 3 things to look for. Live bugs, which are flat, wingless, and reddish-brown, running from about 1 mm as newly hatched nymphs up to 5 to 7 mm as adults.⁷ Cast skins, which look like hollow bedbug shells. And fecal spotting, which is digested blood and looks like small dark dots made with a fine felt-tip pen, usually along the seams and piping of the mattress, in the folds of a pillow top, on the box spring, and on the frame and headboard behind it.

Look after dark, because they hide during the day. Take a bright flashlight, pull the sheets back, and work slowly along the seams and into the crevices, then behind the headboard and into screw holes and joints on any furniture near the bed. Run a sticky lint roller over the areas you are checking; it picks up bugs, skins, and eggs, and it gives you something to seal in a bag and show a professional. If you find nothing after a careful look, that is meaningful information too.

Do bedbugs make you sick?

Not in the way people fear. Bedbugs are not known to transmit any disease between humans, and the EPA and CDC say so jointly; no case or study has shown human-to-human disease transmission by bedbugs.² That is the sentence I want you to hold on to while you deal with the rest of it, because the fear of catching something is doing a lot of the damage here and it is not warranted.

The same joint statement is careful to call them a public health pest, and the consequences it names are the parts a doctor can help with.

The skin reaction itself ranges from nothing at all to large itchy wheals, and the itch is what causes most of the trouble. Scratching breaks the skin, and broken skin gets infected, which shows up as impetigo, ecthyma, or lymphangitis, meaning a spreading red streak tracking away from the bite.¹ Those need treating, and they are the most common reason a bedbug problem becomes a medical problem.

Systemic allergic reactions are described and are rare, including a small number of reported anaphylaxis cases.¹ Iron deficiency anemia from blood loss has been reported too, in heavy sustained infestations, usually in people who were already vulnerable, and low iron carries a long list of symptoms of its own if yours turns up low. Neither of these is what happens to most people, and I mention them so that a page you might read at 2 AM has told you the truth about the whole range.

The health effect that matters most is the one nobody warns you about, and it is psychological. Insomnia, anxiety, hypervigilance at bedtime, nightmares, and avoidance behavior are all well described after an infestation, and in a 2012 series of case reports the pattern was close enough to post-traumatic stress that the authors described it in those terms.³ Work published since has found bedbug exposure associated with mental illness among emergency department patients.⁶ If you have been sleeping on the couch, checking the sheets 4 times before you get in, or feeling things crawl on you long after an exterminator declared the place clear, you are having a documented reaction to a documented stressor. Tell your doctor about that part. It is treatable, and an exterminator cannot help you with it. Anxiety that keeps a body switched on has physiology behind it worth checking when it outlasts the thing that started it.

What else causes bites that look like this?

Several things, and the treatment differs between them, so send me a photo before you settle on an answer.

Scabies is the one I most want to rule in or out, because it is contagious, it will not resolve on its own, and it needs a prescription. It is a mite that burrows into skin, and the itch is famously worse at night. It favors the webs between the fingers, the wrists, the elbows, the waistband, and the genitals, and it often shows up in more than one member of a household. If you can see thin, short, wavy lines in the skin, those are burrows, and they point to scabies.

Flea bites cluster around the ankles and lower legs, and they usually come with a pet, though fleas persist in a home after a pet has gone. Ticks are the other one worth separating out, because that answer runs the opposite way to this page: a tick can transmit disease, and what you do in the first hour changes the outcome. Mosquito bites are seasonal and follow being outdoors. Papular urticaria is a delayed hypersensitivity reaction to insect bites in general and produces crops of itchy bumps that keep coming back, most often in children. Folliculitis, contact dermatitis from a new detergent or fabric, and drug reactions all produce itchy bumps that people arrive convinced are bites.

There is one more situation that deserves saying out loud kindly. Sometimes a professional inspects twice, finds nothing, and the sensation of being bitten continues. That sensation is happening, and it has causes we can look into, including medication effects, thyroid and iron problems, neuropathy, and skin conditions with no visible rash. That is the point to sit down with a doctor instead of searching the mattress a third time, and nobody who has been through it should be brushed off. The same principle runs through our guide to reacting to something when the tests keep coming back normal.

Guidance from the Clinic

"The medicine here is small and the misery is large, and I think that mismatch is why people get such bad advice about it. There is not much for me to prescribe for a bedbug bite. What I can do is tell you whether the thing on your arm is a bedbug bite or scabies, which are handled differently, and treat the skin infection if scratching has caused one. And I can take the sleep part seriously. By the time someone brings this to me they have often not slept properly in weeks, they are checking the bed every night, and they have told nobody because they are embarrassed. That is the part I want to hear about. The bugs belong to a pest control operator and the building belongs to the landlord, but nobody else in that chain is going to ask you how you are doing."

What should you do first if you find them?

Call a licensed pest control operator, and do it before you do anything else, because most of what people try on their own makes the job harder.

Do not spray insecticide you bought yourself. Bedbug populations are widely resistant to the pyrethroid insecticides sold over the counter, so a store-bought spray tends to kill a fraction of them and drive the rest into wall voids and neighboring rooms. A problem confined to one bedroom is far easier to end than the same number of bugs spread through 4 rooms.

Do not throw out your mattress or your furniture. It feels like the decisive move and it is usually the expensive wrong one: dragging an infested mattress through your home and down a stairwell distributes bugs along the whole route, and in a multi-unit building it can seed a neighbor. If a piece has to go, ask the operator first, and seal it fully in plastic before it leaves the room. Many cities require that.

Then, alongside the professional treatment:

• Encase the mattress and the box spring in a zippered bedbug encasement and leave it zipped. Anything sealed inside eventually dies, no new bug can get into the mattress, and the smooth pale surface makes future inspection easy. Ask your operator how long to leave it on; a year is commonly advised. Wirecutter's tested picks are a reasonable place to start, and the features that matter are tight seams and a zipper that cannot creep open.
• Run bedding, clothing, and soft items through a hot dryer for 30 minutes. Heat is what kills bugs and eggs, so anything that is not already soiled can skip the wash.
• Keep it contained. Move things between rooms as little as possible, seal what you are carrying in heavy-duty bags, and take trash bags straight outside.
• Follow the operator's preparation instructions. Treatment usually takes several visits over weeks, and a job half-prepared is a job that has to be repeated.
• Declutter around the bed, which gives the bugs fewer places to hide and gives the treatment a better chance of reaching them.

What are your rights if you rent in Philadelphia?

More than most tenants know, and the protection turns on getting it in writing. Philadelphia has a bed bug ordinance in its property code, § 9-4802, that assigns duties to both sides.⁴ The tenant's job is to notify the landlord in writing, promptly, and to cooperate with the inspection and treatment. The landlord's job is to respond and to hire a pest control professional to investigate and eradicate the infestation, with follow-up inspections afterward.

Who pays depends on how far into the lease you are. Report an infestation in writing within the first year of the lease and the cost of investigating and remediating it falls to the landlord; report it later than that and the landlord still has to handle the remediation while the tenant shares in the reasonable cost. There is also a provision covering infestations discovered in an adjoining unit. The code sets specific deadlines in business days for the tenant's notice and the landlord's response, so check the city's current page for the numbers as they stand and for how to report a landlord who is not complying. Our Philadelphia city health resources guide collects the other city services in the same place.

The practical version is short. Write to your landlord today instead of telephoning, keep a dated copy, photograph what you found, and keep every receipt. None of this is legal advice, and a tenant advocacy organization can give you that; what it is meant to do is stop you from losing a protection you already have by handling it with a phone call nobody wrote down.

When should you see a doctor about bedbug bites?

When the skin looks infected, when the reaction is more than local, or when the sleep has gone. Specifically:

• A bite that becomes hot, swollen, increasingly painful, or starts draining pus
• A red streak spreading away from a bite, or a fever
• Honey-colored crusting over the bites, which suggests impetigo
• Widespread hives, facial or lip swelling, wheezing, or lightheadedness, which need urgent care the same day
• Itching severe enough that you cannot stop scratching or cannot sleep
• Insomnia, anxiety, or intrusive thoughts that persist after the infestation is over
• Bites that continue after 2 professional inspections have found nothing

How does Fishtown Medicine approach this?

By splitting the problem in 2 and being clear about which half is ours. Eradication belongs to a licensed pest control operator, and Fishtown Medicine has no financial relationship with any pest company and does not sell products for this.

The clinical half starts with identification, because the treatment for scabies is not the treatment for a bedbug bite and getting that wrong costs weeks. Dr. Ash will look at photographs of the bites and of whatever you found in the bed and tell you what he thinks it is. From there the work is simple: a topical corticosteroid and an oral antihistamine at night for the itch, antibiotics if scratching has caused a secondary infection, and a proper look at anything that does not fit the story.

The part that usually needs the most attention is sleep, and it tends to outlast the bugs. Treating that means addressing the insomnia directly, not waiting for the anxiety to resolve on its own once the exterminator has finished. If a course of treatment has ended and you still cannot get into your own bed, that is a reason to be seen, and being able to send a message and get an answer the same day matters more here than another appointment does.

If you're in the Philadelphia area and want a physician who will look at the photo and tell you what it is, tell Dr. Ash what's going on at Fishtown Medicine.

Related at Fishtown Medicine

• Insomnia and sleep that will not come back
• Eczema that will not clear
• Rodents in a Philadelphia row home, and which diseases matter
• Is mold making you sick, and how to prove it

Scientific References

1. Goddard J, deShazo R. Bed Bugs (Cimex lectularius) and Clinical Consequences of Their Bites. JAMA. 2009;301(13):1358-1366. jamanetwork.com
2. US Environmental Protection Agency and Centers for Disease Control and Prevention. Joint Statement on Bed Bug Control in the United States. 2010. stacks.cdc.gov
3. Goddard J, de Shazo R. Psychological Effects of Bed Bug Attacks (Cimex lectularius L.). The American Journal of Medicine. 2012;125(1):101-103. amjmed.com
4. The Philadelphia Code § 9-4802, Bed Bugs and Property Rental. codelibrary.amlegal.com
5. City of Philadelphia. Report a bed bug law violation. phila.gov
6. Associations Between Bed Bugs and Mental Illness Among Emergency Department Patients. Journal of Emergency Medicine. ncbi.nlm.nih.gov
7. US Environmental Protection Agency. Bed Bugs: Appearance and Life Cycle. epa.gov