Bed bugs

Background

Bed bugs, Cimex lectularius, are blood-sucking human parasites that are found worldwide. Bed bugs come from the insect family Cimicidae. Bed bugs are oval shaped, flat, reddish brown, and up to 5 mm long. Immature bed bugs are smaller than adults and may be translucent to light yellow.

Bed bugs are attracted by warmth and generally feed at night. They can survive for long periods (e.g. up to one year) without feeding. In developed countries, bed bugs often hide in the cracks and crevices of mattresses, bed frames, and other nearby structures. They can travel in furniture, luggage, and clothing, or can migrate through holes in walls, water pipes, or gutters. In developing countries, bed bugs can be found in the cracks and crevices of the walls of mud houses, as well as thatched roofs. Reports of bed bug infestations appear to be increasing in homes, apartments, hotel rooms, hospitals, and hostels in developed countries. This may be due to increased international travel, immigration, and insecticide resistance.

There is currently no scientific evidence that bed bugs can transmit other human diseases, although there is debate on whether they are implicated in Hepatitis B and Chagas disease transmission.

Clinical features

Bed bugs usually feed without detection by the host, although some people with bed bug infestations report a restless night's sleep. Bed bugs generally bite in a linear pattern (a line) on exposed areas of skin such as the face, neck, hand, and arms. Most patients do not experience a reaction to a bed bug bite, and the only evidence is a tiny punctum (hole) at the site of the bite.

When a reaction occurs, the lesions are most commonly 2 to 5 mm red, itchy bumps. If they are not scratched they usually resolve in a week or so.

Some people experience significant skin reactions to the bites including:

• Itchy wheals around a central punctum
• Papular urticaria
• Diffuse urticaria

These reactions may evolve into a bullous rash (fluid-filled blisters) and may become complicated by secondary bacterial infections such as impetigo or cellulitis.

Systemic reactions that have been rarely associated with bed bugs include asthma and anaphylaxis.

Bed bug bites

Treatment of bed bug bites

Treatment is not generally required. However, various treatments may relieve the symptoms of bed bug bites:

• Severely itchy lesions can be treated with topical steroids and/or oral antihistamines.
• Secondary infection should be treated with antibiotics.
• Systemic reactions to bed bug bites are treated with antihistamines, corticosteroids, and intramuscular adrenaline.

Eradication of bed bugs

Firstly bed bugs must be correctly identified. A thorough search of the cracks and crevices of the bed and surrounding areas should be undertaken to detect the easily visible bed bugs or their faecal matter.

Eradication of bed bugs can be difficult and requires chemical and non-chemical control strategies:

• Chemical control – insecticide spray or insecticide-treated bed nets may be moderately effective against bed bugs. However use of these products has raised concerns about the health consequences of exposure to insecticides and the development of insecticide resistant bed bugs.
• Non-chemical control – methods include vacuuming, heat treatments, laundering, mattress and box spring encasements, and destroying infested objects. Washing and drying items in a dryer on a hot setting is sufficient to kills bed bugs in clothing or linen.