Bed Bugs

Bed bugs are small, flat, wingless insects that live in cracks near where people sleep and feed on human blood, mostly at night. They aren't known to spread disease, but they're one of the hardest household pests to eliminate, mostly because the first things people try (a can of spray, a fogger, a weekend away) don't work.

This page covers how to tell it's really bed bugs, where they hide, how fast they multiply, and the realistic options for getting rid of them. For the step-by-step plan, go to how to get rid of bed bugs.

What bed bugs look like

The common bed bug in US homes is Cimex lectularius. In Florida and other warm areas you may also find the tropical bed bug (Cimex hemipterus), which looks and behaves almost the same and is treated the same way.

• Adults: 3/16 to 1/4 inch long (5–7 mm), oval and flat as paper when unfed, mahogany to reddish-brown. University of Kentucky entomologists describe them as apple-seed colored but closer to the size of a lentil. After a meal they swell, lengthen and turn darker red. They have six legs, two antennae and no functional wings.
• Nymphs ("small bed bugs"): five stages from about 1 mm up to adult size. They're pale straw-colored and almost translucent until they feed, and then a bright red blob of blood shows through the body. These are what people most often miss, and what they find crawling on a pillow in the morning.
• Eggs: about 1 mm, pearly white, glued in clusters into seams and cracks. Empty shells stay stuck in place after hatching. See bed bug eggs.

Bed bugs can't fly or jump; they crawl about as fast as an ant (can bed bugs fly?). Many insects get mistaken for them: carpet beetles, bat bugs, booklice, spider beetles, ticks and young cockroaches. Bat bugs and swallow bugs are close relatives that can only be separated under magnification, and they need a different fix (dealing with the bats or birds). If you've caught a specimen, compare it on our bed bug look-alikes page, or tape it to a card and take it to your county extension office, which will identify it for free.

Signs you have them

Pest professionals diagnose bed bugs from physical evidence, not bites:

1. Dark spots on sheets and mattress seams: digested blood that looks like marker dots and soaks into fabric instead of brushing off.
2. Rust-red smears on sheets or pillowcases from a fed bug crushed in your sleep.
3. Shed skins, eggs and live bugs in seams, the box spring and bed frame joints.
4. Bites in rows or clusters after sleeping on arms, neck, shoulders and back. These are a clue only: UC IPM warns that bites "should never be used for diagnosis." More on bed bug bites.
5. A sweet, musty odor, which you'll only notice in heavy infestations.

Show photoclose-up of an insect or bite, you can hide it again

Full inspection walk-through, including hotel rooms: signs of bed bugs.

Where bed bugs hide

Bed bugs want to be close to a sleeping host and wedged into a crack where their back and belly both touch a surface. Their flattened bodies fit into gaps the width of a credit card. UC IPM puts about 85% of a typical infestation in or near the bed. In University of Kentucky field studies of infested apartments, nearly all bugs were on beds and sofas:

The box spring finding surprises most people, who only check the mattress. Check, in this order:

• Box spring: top seams, the fabric underside, and the wooden frame inside it
• Mattress seams, piping, tags and handles
• Bed frame joints, screw holes, slat ends, and the back of the headboard
• The couch or recliner if anyone sleeps or naps there: seams, under the skirt, inside the frame
• Nightstand drawers and joints
• Baseboards and carpet edges behind the bed, outlet and switch plates, picture frames, loose wallpaper

Bed bugs prefer wood, paper and fabric to metal and plastic. In apartments, they also travel through wall voids, pipe chases and shared outlets, which is why a unit next to a treated one often gets them next.

What bed bugs eat and how they live

Bed bugs eat nothing but blood. They find you by the carbon dioxide you exhale and by body heat, so they come out mostly in the hours before dawn. They feed for 3 to 10 minutes, taking up to six times their weight in blood, then crawl back to hide for several days while they digest. Their saliva contains an anesthetic, which is why you don't wake up. If you sleep during the day, they shift their schedule to match. Sleeping with the lights on doesn't stop them.

UC IPM's life-cycle numbers:

• A female lays 200–500 eggs in her life, usually 2–5 a day.
• Eggs hatch in about 1–2 weeks at room temperature.
• Each of the five nymph stages needs a blood meal to molt. Egg to adult takes 5 weeks to 4 months, fastest at 70–82 °F.
• Adults live a year or more, with up to four generations a year.

That's why a "few bugs" in month one becomes a real infestation by month three.

They're also tough. University of Kentucky entomologists put typical survival without feeding at 1–4 months in a heated building, and a year or more below about 55 °F. Leaving home for a week or two doesn't starve them out.

Are bed bugs dangerous?

Not in the way ticks or mosquitoes are. The CDC states bed bugs are not known to spread disease to people. The real problems are:

• Itchy welts that can last a week or more; scratched bites can get infected.
• Allergic reactions in some people: large swelling, rarely blistering, and very rarely anaphylaxis. See a doctor if a bite area keeps spreading, is hot and painful, has pus, or you develop a fever.
• Anxiety and lost sleep, which people who've lived through an infestation consistently describe as the worst part.
• Harm from DIY. EPA warns that rubbing alcohol, kerosene and gasoline sprayed on beds have caused fires, and that raising the thermostat or using space heaters to "cook" bed bugs doesn't work and is dangerous. Outdoor pesticides used indoors cause poisonings.

Where they come from

Bed bugs don't come from dirt. They're carried in: in luggage after travel, in used furniture and mattresses, on visitors' belongings, or through walls from a neighboring apartment. Hotels, dorms, shelters, rentals and multi-unit buildings are where they spread most, but the CDC notes they're found in five-star hotels too. More detail: what causes bed bugs.

What people who dealt with it say

Threads in r/Bedbugs and r/pestcontrol tell a remarkably consistent story:

• Late detection is the rule. Most people spent weeks or months blaming mosquitoes, hives or allergies. Often one family member had all the welts while the others, non-reactors, had none.
• The first moves that failed were nearly always the same: foggers, diatomaceous earth sprinkled across floors, sleeping on the couch, throwing out the mattress, or moving before treatment. All of these spread the bugs or left survivors.
• What worked: acting on the first confirmed bug; isolating the bed (encasements, interceptors, bed off the wall); thin silica gel dust in cracks; and professional treatment repeated two or three times about two weeks apart, or whole-unit heat followed by a residual product.
• How long it took: people who caught it early and had a responsive landlord or pest company often report 3 to 7 weeks. People in apartments with neighbors who weren't treated, or who started late, report 6 months to a year.
• What it cost: one family paid about $2,000 for heat treatment on their home's main level plus two follow-up sprays and called it the best money they'd spent. Apartment quotes around $1,200 are common. Some tenants report landlords trying to bill them.
• What pros say: severe cases almost always need retreatment, and product choice and thoroughness vary a lot between companies. Get a written follow-up or re-treatment guarantee, and in apartments, insist adjoining units are inspected.

Pest control for bed bugs: your options

There are three realistic routes, and the right one depends on how big the problem is:

What fails, almost every time:

• Total-release foggers ("bug bombs"). Ohio State researchers found that wild bed bugs survived fogger exposure, and the mist doesn't reach the cracks where they hide.
• Store-bought pyrethroid sprays on their own. Many US populations are resistant.
• Diatomaceous earth as the main weapon. In a University of Kentucky apartment field trial, thorough DE treatment left populations essentially unchanged. Silica gel dust performs much better.
• Essential-oil sprays, ultrasonic devices, and throwing out the bed while leaving the frame, nightstand and baseboards untreated.

Professional bed bug treatment in the US typically costs roughly $300–$1,500 for a single room or small apartment and $1,500–$5,000+ for whole-home heat. These are approximate ranges that vary widely by region. Compare quotes on pest control cost. A good company will inspect first, explain prep, and include at least one follow-up visit.

Preventing bed bugs

• After travel, put the suitcase on the luggage rack, not the bed or floor, and check the head end of the mattress and behind the headboard. At home, unpack outside the bedroom and put clothes straight into the dryer on high for 30 minutes.
• Inspect used furniture with a flashlight before it comes inside. Skip used mattresses and upholstered pieces from the curb.
• Encase the mattress and box spring in zippered, bed-bug-proof covers. It removes hiding places and makes checks easy.
• Install interceptor cups under bed legs. They trap bugs climbing up and act as an early-warning monitor.
• Seal cracks along baseboards and around pipes, especially on walls you share with neighbors.

If you're seeing bites but aren't sure, start with an inspection rather than spending money on treatment. The signs page shows exactly how.