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Don't let the bedbugs bite

Siobhan Hicks
RGN BSc
Nurse Practitioner in Primary Care
Lecturer in Public
Health and Primary
Care
London

It has been reported that bedbugs have been making a comeback in recent years, but what is the truth behind this statement? The pest control company Rentokil has stated that complaints about bedbugs are up 52% in 2006/7, especially in Manchester, which has seen a 179% rise in reported cases. Travel, tourism, the popularity of secondhand goods and global warming have been cited as possible causative factors.(1)
Interestingly, before the Second World War bedbugs were abundant. In the UK the situation was reported as "in many areas, all the houses are to a greater or lesser degree infected with bedbugs".(2) Bedbugs have always been common in areas of extreme poverty, but it is now thought that they are undergoing a rapid resurgence in the developed world.

What are bedbugs?
Bedbugs are cosmopolitan creatures found worldwide, measuring 5 mm in length. They are oval and flat in shape without wings, often resembling unfed ticks. The adults are chestnut in colour and immature bugs are yellow or white. A large probiscus (tubular mouthpart) is tucked under their head and chest, which is used for piercing and sucking blood. The bug also has stink glands near to the abdomen, which produce a pungent smell.
Female bugs will cement their eggs to anything and can produce six to 10 eggs per week. They live for about 10 months and in laboratory conditions have been found to live for up to four years without food.(3) Bedbugs spend their time concealed in areas such as mattresses, bed frames, behind pictures and coving, in curtains, under fitted carpets and in wall voids or loose wallpaper. They are rarely found on a person.
It is impossible to estimate the prevalence of bedbugs or their bites in the UK because of the scarcity of new reported finds to the Public Health Laboratory Service.(4) As a result, many clinicians are unfamiliar with bedbugs and their bites, and very often misdiagnose the bites as scabies or other skin conditions.

How do you know if you have been bitten?
An insect bite is a puncture wound or laceration by an insect. An antigenic salivary gland secretion in the bite produces local inflammation, but rarely causes systemic effects.(5) Diagnosis is self-evident, with constant irritation made worse by scratching and rubbing. Papular urticaria (widespread raised wheal-like itchy lesions) is common in children, especially if they have a history of atopic dermatitis.(6) Lesions usually occur in the area of the bite and may be grouped on exposed areas and remain itchy for up to two weeks.
Careful history taking will reveal the origin of the bite. Remember to ask if the patient has had a recent house move, bought secondhand furniture, had any recent travel or seen a bug. It is important to rule out within the differential diagnosis, eg, cellulitis, chicken pox, urticaria, contact dermatitis or scabies. Most insect bites are self-limiting, but secondary bacterial infection can occur as a result of scratching.

Identifying and treating the infestation
Bedbugs feed on the sleeping and hide once they have secured a feed; they can only be seen if searched for at night. Other clues, such as blood spotting on bed linen and a heavy unpleasant almond smell, can indicate their presence. If suspected, contact a reputable pest control company so that thorough treatment with a residual insecticidal spray or powder can be carried out, often more than once.
Assess the severity of the bite, especially for secondary infection. Small local reactions respond well to cold compress, oral analgesia, topical crotamiton, topical hydrocortisone or oral antihistamines (avoid in pregnancy).(7)
Follow-up is not generally needed unless the symptoms do not resolve.

Complications
Very rarely a patient may progress to a large local reaction after being bitten; this may need treatment with a short course of oral antihistamine, oral analgesics or oral steroids. If the airway is affected, treat urgently as anaphylaxis. Ultimately, you may wish to consider referral to an allergy clinic if any previous bite has caused generalised symptoms.(7)
As well as the health implications of infestation, the personal and financial implications can be considerable due to the disposal and replacement of furniture and fittings. Hotel chains are concerned about potential financial and public image costs. In March 2007 an American lawyer took legal action against a hotel in London after being covered in bedbug bites.(1)
Another concern is the risk of transmission of infection. A bite may become secondarily infected, in which case the firstline treatment is with flucloxacillin or a macrolide if penicillin allergic.7 However, reassurance can be given as research has consistently shown that bedbugs do not transmit bloodborne infections such as HIV and hepatitis.(8,9)

Prevention
Before insecticides, burning mattresses that gave off a characteristic stench was the norm and in the 19th century bedbug traps consisting of flat woven baskets were placed in the bolster of the bed overnight - it is thought the smell of trapped bedbug faeces attracted free bedbugs.(8)
DDT (dichlorodiphenyltrichloroethane) destroys bedbugs, but this is now banned due to its toxic effects and there was a question over increasing resistance. Insecticides such as malathion or pyrethin-based agents such as delamethrin can be used to fumigate bedding and infested rooms, but only under specialist advice. After fumigation all areas should be thoroughly vacuumed and cleaned; obviously when using pesticides follow all directions to lessen the danger to children and pets.
Fumigation is the only treatment for the destruction of bedbugs. If patients are anxious for other preventive advice, you may wish to consider the following:

  • The local council or pest control expert may need to fumigate the house.
  • To repel an insect bite, use a repellent that contains 50% DEET (diethyl-m-toluamide).(10) There is no evidence that this is harmful to children or pregnant women and it provieds up to 12 hours protection.

Conclusion
There is little medical evidence at present to confirm that bedbugs are making a comeback in the UK, but it has been suggested by Rentokil that there may be an increase of prevalence given the rise of international travel, trade and tourism. It would be fair to say on this evidence that it is possible that they are making a comeback. Bedbugs have lived on this planet long before humans and will probably remain long afterward. We can learn how to control them, but elimination may be impossible.

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References

  1. March of the bedbug. Guardian Unlimited. July 2007. Available from: http://www.guardian.co.uk
  2. Ministry of Health. Report on committee on the eradication of bedbugs. Report no 72. HMSO; 1933.
  3. Service M. Bedbugs. In Lecture notes on medical entomology. Oxford: Blackwell Scientific Publications; 1986.
  4. Paul J, Bates J. Is infestation with the common bedbug increasing? BMJ 2000;320:1141.
  5. Burns D. Diseases caused by arthropods and other noxious animals. In: Rooks textbook of dermatology. 7th Ed. Oxford: Blackwell Science; 2004.
  6. Clinical Knowledge Summary. Insect bites and stings. Available from: http://www.ckslibrary.nhs.uk
  7. BNF 52. British national formulary. London: BMA RSPGB; 2006.
  8. Boase C. Bedbugs - back from the brink. Pesticide Outlook 2001;12:159-62.
  9. Silverman A, et al. Assessment of hepatitis B virus DNA and hepatitis C virus RNA in the common bedbug and kissing bug. Am J Gastroentrol 2001;96:2194-8.
  10. Healthcare Protection Agency. Taking a walk on the wild side? Be tick aware says the HPA. London: HPA; 2007. Available from: http://www.hpa.org.uk