Clinical Notes : Dermatology

197. Bedbug bite


What is a bedbug ?

The bed bug, Cimex lectularius, is a blood-sucking human parasite that is found worldwide.

Bed bugs come from the insect family Cimicidae.

The bed bug is 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.

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More about bedbugs

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.


What are the clinical features of bedbug bites ?


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:


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.

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What is the treatment for bed bug bites ?

Secondary infection

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

  • 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.

Hire a licensed professional pesticide applicator with experience in treating bed bugs. 

  • Chemical control — insecticide spray or insecticide-treated bed nets.  

  • Non-chemical control — methods include vacuuming, diatomaceous earth spray, heat treatments, freezing, and laundering of mattress and box spring encasements, and destroying infested objects. Heated pitfall traps collect the bugs.

  • Washing and drying items in a dryer on a hot setting is sufficient to kill bed bugs in clothing or linen.


Once clear of bed bugs prevent recurrence by enclosing mattress and pillows, removing clutter, and reducing hiding places for the bugs.

Each bed leg or caster can be placed in a container of talcum powder or wrapped in adhesive tape (sticky side out) to act as a barrier to the bugs. 

  • Check second-hand furniture before purchase. Avoid buying a second-hand mattress.

  • Wash second-hand bedding and clothing in hot water before use.

  • If travelling, check every hotel room for bed bugs. Keep your bags off the floor. When you get home, hotwash your clothes, and thoroughly vacuum your bags. Seal the vacuum bag before destruction.


Bed bug 

DermNetNZ  (CCPL)


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Pest control company Rentokil reported that bed bug call outs upped by 61 % when comparing the 2019 January to April period with the same period in 2018.

Dublin is the county with the most call outs, with 36 per cent of all bed bug call outs.

Galway at 14 %, Cork at 10 % and Kerry at 8 % are the next three counties which accounted for the most call outs in relation to bed bugs.


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