Bedbugs

What are bedbugs?

Bedbugs are blood-sucking insects which feed from humans. They often live in bedding, beds and in cracks and crevices of surrounding walls and furniture. They may cause skin reactions and psychological effects, but are not known to transmit disease.

How common are bedbugs? (Epidemiology)¹

The increase in pyrethroid resistance, the ban of DDT, immigration and international travel, the increased population density in large cities, and a decrease in societal vigilance have led to an exponential rise in the incidence of bedbug infection.

Therefore, over the past decade or two, bedbugs have made a dramatic comeback and are increasingly common in homes, apartments, hotels, healthcare facilities and schools.

Aetiology²

• The two main species of bedbugs are Cimex lectularius and Cimex hemipterus. Cimex lectularius are found in temperate areas. Cimex hemipterus are found in tropical zones.

• Bedbugs are brownish, wingless, flattened insects, measuring around 2-5 mm in length.

• They feed solely on the blood of animals. In addition to humans, they will also bite other warm-blooded animals (eg, dogs, cats and rodents).

They can actually survive for up to one year without eating. The ability to survive without a blood meal is longer at cooler temperatures. The adults can live for up to 18 months. They breed by laying eggs which hatch after around 10-20 days and take between 9-18 weeks to become adults. Females can lay around 300 eggs in their lifetime.

They are sometimes mistaken for ticks, cockroaches or carpet beetles. The immature bedbugs (nymphs) look much like the adults, other than being smaller and a lighter brown.

Bedbugs can crawl rapidly over floors, walls, ceilings and other surfaces. They cannot jump or fly. Bedbugs are inactive during the day, often hiding in dark places (eg, mattresses, bed frames, within plug sockets, in clothing or soft furnishings, in cracks and crevices of wooden furniture).

They live in both clean and dirty environments.

Bedbug on skin

Content Providers(s): CDC/ Harvard University, Dr. Gary Alpert; Dr. Harold Harlan; Richard Pollack. Photo Credit: Piotr Naskrecki, Public domain, via Wikimedia Commons

Symptoms of bedbugs²

As bedbugs feed at night and inject an anaesthetic when they bite, the initial bite is usually not felt and most patients have no reaction to them. The biting process takes up to ten minutes but the person being bitten is usually unaware of it. The symptoms following being bitten by bedbugs vary but include:

• Little or no reaction. This is the case for most affected individuals.

• Three to four bites forming a line or a curve on the body (usually areas exposed during sleeping such as face, neck, arms) are very suggestive of bedbug bites.

• Isolated pruritus, papules or nodules can occur. Skin reactions most often start out as small macular lesions that can develop into wheals of around 5 cm in diameter. These are often intensely itchy.

• Occasionally, bullous eruptions may occur.

• Rarely, systemic reactions occur (eg, urticaria or even anaphylaxis).

• The onset of symptoms may be delayed, due to delayed allergic reactions to the saliva of the bedbug (up to 11 days later).³

Bedbug bites on face

Original uploader was Andybrookestar at English Wikipedia, Public domain, via Wikimedia Commons

Differential diagnosis²

• Bedbug bites may be mistaken for bites from fleas or bites from mosquitoes or other arthropods. Bites from fleas tend to be on lower legs or ankles.

• Scabies. Scratching in patients with scabies is more often in the wrists, fingers and around the waistline.

• Chickenpox.

• Other dermatological conditions which may be similar include:
  

  • Erythema multiforme.

  • Sweet's syndrome.

  • Bullous dermatitis.

  • Vasculitis.

  • Dermatitis herpetiformis.

How to get rid of bedbugs¹

Treatment is mainly symptomatic, with oral antihistamines and topical corticosteroids to reduce pruritus and alleviate the dermatitis. Patients should be instructed to avoid scratching to prevent infection. Secondary bacterial infection can be treated with topical or systemic antibiotics. Measures to eradicate the infestation are critical to therapy.

Control of infestation is difficult because of the ability of bedbugs to hide in furniture cracks and crevices, and their ability to survive long periods of time without feeding. The following non-chemical measures may be beneficial:⁴

• Washing at 60°C or dry cleaning affected linen.

• Tumble drying affected linen on a hot cycle for at least half an hour.

• Freezing may also be effective; however, affected items must be kept frozen for at least one or two weeks.

• Disposal of highly infested items, together with physical removal of bedbugs and mattress covers and vacuuming, are usually recommended.

• Encasing mattresses in a protective covering (such as those used for people with allergies) may be an option; however, the seal needs to be tight, with no gaps in the encasement material.

Insecticides must be used only by professionals and it is recommended that expert guidance regarding eradication should always be sought.

Pyrethroids are the most commonly used insecticides for bedbug infestations.

Insect growth regulators and carbamates are also sometimes used. However, resistance to all types of insecticides has occurred. Therefore, a combination of insecticides is usually applied to all areas. Re-treatment may be indicated in some areas.

Carbon dioxide fumigation has been shown to be an effective alternative to conventional fumigants for eliminating bedbugs hiding in infested household items such as clothing, sofas, shoes and books.⁵ Fumigation for at least 24 hours is required.

Treatment of bedbug bites²

• The symptoms of bedbug bites are often treated with topical steroids (such a hydrocortisone 1%) once or twice a day for up to seven days.

• Antihistamines may be beneficial for those with pruritus.

• Topical or systemic antibiotics may be necessary for those with secondary infection of their bites.

• People with an infestation should be encouraged to contact a pest control expert as soon as the pest has been identified.

Complications

Secondary infection from scratching can occur.

Although bedbugs have been suspected of transmitting infectious agents (eg, hepatitis B, hepatitis C, HIV or meticillin-resistant Staphylococcus aureus (MRSA)), no report has yet actually demonstrated that they are infectious disease vectors.⁶

Sleep deprivation is common, with consequent social and health sequelae.⁷ In some individuals, psychological sequelae can result from bedbug biting events. These may include nightmares, flashbacks, hypervigilance (to keep the bugs away), insomnia and anxiety.⁸