Bedbugs are wingless, flat, reddish-brown, oval, and about the size of an apple seed. They are nocturnal and feed on the blood of warm-blooded hosts. In homes, they tend to live near beds: in mattress seams; sheets; furniture; behind loose wallpaper, electrical wall plates, and baseboards; underneath carpet and rugs; in picture frames; and in wall and ceiling cracks.

Because they are small and flat and can hide just about anywhere, they are difficult to detect early on and therefore often bring about major infestations—you’ll usually detect them only after they’ve chewed on you a bit. Bedbug bites usually aren’t painful when they occur, but they often result in itchy red welts the day after. These welts vary in appearance from tiny pinpricks to mosquito-bite-sized bumps to very large welts. Some people have no noticeable reaction to bedbug bites.

Other signs of a bedbug infestation are small bloodstains on bedding (as victims roll over and squash the bugs in their sleep) and clusters of small dark-brown or black dots on infested surfaces (bedbugs’ dried excrement).

There is no link between bedbugs and the spread of disease, though their bites can cause infections. But the stress and sleep deprivation that result from a bedbug infestation often create other health concerns.

How to Stop Them

As they are incredibly resilient and can become resistant to pesticides, bedbugs are notoriously difficult to control. They typically feed every five to 10 days, but if no food source is available they can survive for a year or more without any victims to chew on. They are excellent hitchhikers and multiply quickly—even one critter or egg sac transported from an infested site on an item of clothing or in a suitcase can produce a new population in your bedroom. Because they don’t live in colonies, when infestations occur the entire area must be treated, possibly several times. Even small infestations may require calling in a pro.

Unlike many other household pests, sanitation won’t prevent bedbugs or get rid of them. But since clutter provides them with perfect hiding spots, the first step toward eliminating a bedbug infestation is to clear out everything in the room but the furniture. Put items in airtight plastic bags and seal them before you leave the room; otherwise you’re giving the bedbugs the chance to spread.

Then, thoroughly vacuum beds and carpets. Remove electrical outlet and lighting switch plates, and vacuum the dust and debris inside (after you’ve shut off the circuit breaker!). Pull carpeting off its tack strips around the perimeter of the room (one side at a time) so you can thoroughly vacuum baseboards and underneath the edges of the carpeting. Immediately dispose of the vacuum bag outdoors afterwards.

Wash everything that’s washable in the hottest water it can take (120°F or higher), and dry at the hottest setting possible. Have carpets and rugs professionally cleaned.

Now you can take on any remaining bugs. Pest control services use a variety of pesticides to zap bedbugs, but since they have to treat surfaces where skin exposure occurs, they most commonly apply pyrethroids and isopropyl alcohol. The alcohol kills bugs on contact and evaporates quickly, leaving minimal residue. The drawback: Without any residue, the agent won’t stick around long enough to kill the bedbugs that survived the previous treatment. But even one treatment should knock a bedbug infestation down to manageable levels; and since its dehydrating effect also affects bedbug eggs, repeated treatments, along with washing and vacuuming, should eventually eliminate them.

Hiring Help

Since bedbug infestations are so challenging, many people hire professionals to tackle them. You’ll probably need a series of treatments to get rid of them, unlike many other pest problems.

Ask any company you consider to describe in detail what it will do and how it will do it. Request a written guarantee that lasts for at least a year and a commitment to return and re-treat as many times as necessary to eliminate the infestation. If subsequent visits are to be billed on a per-visit basis, get the details in writing.