Patient information: Bedbugs (Beyond the Basics)
- Dirk M Elston, MD
Dirk M Elston, MD
- Professor and Chair, Department of Dermatology and Dermatologic Surgery
- Medical University of South Carolina
- Stephen Kells, PhD
Stephen Kells, PhD
- Associate Professor of Entomology
- University of Minnesota
Bedbugs are small insects that can infest homes and other structures. There are several species of bedbugs, one of which (Cimex lectularius) is responsible for the majority of infestations in temperate (moderate) climates; another species can be found in more tropical areas. There are also related species known as "bat bugs" and "bird bugs", which infest the habitats of those animals. A microscopic examination may be necessary to distinguish bedbugs from other species.
This topic will review how to determine if bedbugs are present, how to treat bedbug bites, and how to eliminate a bedbug infestation.
WHERE ARE BEDBUGS FOUND?
Human bedbugs are found around the world and can infest any structure or site where people may rest. Bedbugs tend to be more common in apartment buildings, other multi-family facilities (eg, homeless shelters), and hotels. Historically, they have also been found in public transportation systems and entertainment venues.
Bedbugs from tropical areas can be transported to non-tropical locations by international travelers, who unknowingly carry the insects on their clothing or luggage. If bedbugs are seen during travel, clothing and luggage should be inspected and cleaned before re-entering one's own home. Washing clothing and then drying it in an electric clothes dryer on the hot setting is adequate to kill bedbugs.
Bedbugs feed on the blood of warm-blooded animals, including humans; they are attracted by warmth and carbon dioxide, and tend to bite when a person is asleep or still for a period of time. They favor cracks and crevices in mattresses, cushions, bed frames, in the folds of curtains, behind loose wallpaper or baseboards, and in clothing or other items on the floor. During a heavy infestation, bedbugs may spread to other items in the room, as well as to adjacent rooms.
The females also lay eggs in these locations, which hatch after four to 10 days. Because bedbugs typically hide during the day, they are often not seen or suspected until bites to the skin are observed.
Bedbugs are small and wingless (non-flying), with flat oval-shaped bodies and six legs (picture 1). They are reddish-brown in color, and may appear redder after feeding on blood. Adult bedbugs reach about 0.25 inches (5 to 7 mm) in length, and the body elongates and widens after a meal.
As bedbugs molt (shed their skin) several times throughout their lifetime, cast-off skins may occasionally be visible at the site of a previous or current infestation.
REACTION TO BEDBUG BITES
It takes five to 10 minutes for a bedbug to complete a "blood meal", or feeding. Bedbugs often inflict a series of bites in a row, and typically target exposed areas of skin (eg, face, neck, arms, hands). The bite itself is generally painless, and may not be noticed until the person awakens or even a day or two later.
Reactions to bedbug bites vary; some people have few or no symptoms, while others experience a more severe reaction. Typically, bedbug bites appear as small, red and swollen areas on the skin, often with a point or dot visible in the center. The area is usually itchy, and may resemble urticaria (hives), a common skin reaction that is often triggered by contact with an allergen. (See "Patient information: Hives (urticaria) (Beyond the Basics)".)
Bedbug bites usually take three to six weeks to heal, although new bites are likely to accumulate even as the older ones disappear as long as the infestation is still present. Bites may become infected, particularly if the person scratches at and further irritates the skin.
Psychosocial aspects — People affected by bedbugs may experience significant levels of stress and anxiety as a result of concerns about spreading the infestation. However, with the proper measures, bedbugs can be eliminated safely and successfully. Feelings of panic, depression, or extreme anxiety or despair should be discussed with a healthcare provider.
DO I HAVE BEDBUGS?
Bedbug bites — Bedbug bites can be difficult to distinguish from other insect bites; however, several clues can suggest the presence of bedbugs. The discovery of red, itchy bites upon awakening (see 'Reaction to bedbug bites' above), particularly if they form a line or row on the skin, should arouse suspicion.
Other conditions that may produce symptoms similar to bedbug bites include:
●Scabies — A mite infestation which causes intense itching, scabies also causes red lesions; however, unlike bedbug bites, they are usually not limited to exposed skin, and are sometimes accompanied by signs of a burrow (small line in the skin).
●Insect bites — Bites from fleas, mites, and other small bugs or insects can cause redness, swelling, and itching of the skin.
●Other skin disorders — Conditions such as dermatitis herpetiformis, a skin eruption caused by an allergy to gluten (a protein found in wheat), can also resemble the reactions caused by bed bug bites. Other allergies, aggressive washing, and use of some cleaning products can also cause skin irritation.
Signs of infestation — Minor bedbug infestations are often difficult to detect, as the bugs themselves are rarely seen due to their small size and tendency to hide in cracks and crevices during the day. Small reddish-brown specks of dung found on linens, mattresses, or walls surrounding the bed may suggest the presence of bed bugs.
Severe or widespread infestations can cause a coriander-like odor that may be recognizable to those familiar with it; however, this is not usually helpful when trying to diagnose bedbug bites. The only way to definitively identify a bedbug infestation is to collect a specimen (bedbug) and send it to an expert for evaluation and identification. In the United States, most states have an extension office or entomology department at a local university that can perform this service; other options include contacting the local health department or a pest control service. A bedbug specimen may be stored in a plastic pill bottle, zipper top plastic bag, or taped to a piece of white paper.
CAN BEDBUGS CARRY DISEASE?
In general, bedbugs are not known to spread pathogens (germs) that can cause disease in humans. Further research is needed to fully understand the possible connections between bedbugs and other diseases.
Symptoms — Bedbug bites can be treated with non-prescription lotions or creams that contain pramoxine (eg, Sarna®, Aveeno Anti-Itch®, Neutrogena Skin Aid®). Intense itching can be managed with a corticosteroid (steroid) cream or ointment, which can be purchased at most pharmacies.
If symptoms improve with treatment, do not assume that the bedbugs have been eliminated. If an infestation is present, it is important to identify and manage the situation in addition to treating the bites themselves. (See 'Infestation' below.)
Keeping the skin clean and dry and avoiding scratching will help bedbug bites to heal faster and avoid becoming infected. If the area develops signs of skin infection (eg, redness, swelling, pus-like discharge), a healthcare provider should be consulted.
Infestation — Before bedbugs are treated, it is important to be sure that bedbugs, rather than another insect, are present. If bat bugs or bird bugs are suspected, bat roosts and/or bird nests in the area should be inspected and eliminated if they appear to be infested. Fleas, mites, and even springtails may be mistaken for bedbugs.
Pest control treatment — If human bedbugs are definitively identified, a licensed pest control operator or service should be contacted to inspect the area, design a treatment plan, and apply chemical insecticides as appropriate. Victims of infestation should NOT attempt to apply pesticides or other chemical control measures themselves. Elimination of bedbugs requires trained and knowledgeable professionals.
Rented or leased units — People who rent or lease their home should contact their landlord for assistance; depending upon the rental contract, the owner of the property may be required to pay for treatment by a licensed pest control service. Inspection and treatment, if necessary, of adjacent apartment units is absolutely essential regardless of whether bedbugs have been seen.
Cleaning suggestions — To aid in control of the infestation, clean the affected area thoroughly by vacuuming, laundering, and removing clutter. Washing clothing and then drying them in an electric clothes dryer is adequate to kill bedbugs; the dryer should be placed on the hottest setting the fabric can withstand. Remove drawers from furniture and vacuum cracks and crevices. Encasing the mattress and box springs in a zippered fabric case will make it easier to detect remaining and future infestations.
Bedbugs may enter the house through cracks in walls and doorways. These can be sealed or treated with an appropriate insecticide. However, attempts to seal all openings in a room or house (such as caulking between the walls and baseboards) are unlikely to be successful and may actually prevent insecticide treatments from penetrating into areas where bedbugs hide. Peeling paint and cracked plaster must be eliminated.
It is usually not necessary to dispose of furniture or bedclothes entirely. If a person chooses to discard an item, it should not be left on the street or given away because this can allow further spread of bedbugs in the community.
WHERE TO GET MORE INFORMATION
Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
The following organizations also provide reliable health information.
●National Library of Medicine
●The Nemours Foundation
(http://kidshealth.org/kid/ill_injure/bugs/bedbug.html, available in Spanish)
●University of Minnesota Department of Entomology
●University of Kentucky Department of Entomology
UpToDate wishes to acknowledge Kelly Crowley for her contributions to this topic.
- Kells SA. Bed bugs: a systemic pest within society. Am Entomol 2006; 52:107.
- Thomas I, Kihiczak GG, Schwartz RA. Bedbug bites: a review. Int J Dermatol 2004; 43:430.
- Cleary CJ, Buchanan D. Diagnosis and management of bedbugs: an emerging U.S. Infestation. Nurse Pract 2004; 29:46.
- Elston DM, Stockwell S. What's eating you? Bedbugs. Cutis 2000; 65:262.
All topics are updated as new information becomes available. Our peer review process typically takes one to six weeks depending on the issue.