Bedbugs

A 26-year-old man presents with itchy red marks on his arms and legs, present since he returned from a weekend away 3 days earlier. On examination he has clusters of small red macul0-papular spots and you suspect bedbugs. What should you do to manage his rash, and what advice does he need to eradicate a possible bedbug infestation?

Bedbug infestations have increased dramatically in the past 30 years, partly due to increased global travel but also because of developing resistance to insecticides. In primary care, it can be difficult to distinguish bedbug bites from other insect bites, and suggestive skin lesions should prompt thorough examination of the home/possessions for evidence of bedbugs (NEJM 2020;382:2230).

Bedbugs are fast moving, and rapidly reproducing, flat brown insects. Adults are about the size of an apple pip (5– 7mm long). They cannot fly or jump. They feed on human blood and are mainly nocturnal. 

Bedbugs can hide in clothing, textiles, bedding, mattresses, bedframes, furniture, behind wallpaper and inside electrical sockets and ducting. 

Diagnosis

  • Bites are usually painless, and occur on exposed skin areas such as arms, legs, feet, face and neck.
  • Pruritic, maculo-papular, erythematous spots 2–5mm in diameter, usually without a central visible punctum. The bite usually appears immediately but can take 1–2 days to show.
  • Bites tend to occur in a straight or zigzag line, or 3–5 bites in clusters: the breakfast, lunch and dinner sign (although other insect bites can also have this pattern).

Complications

  • Pruritus.
  • Urticaria.
  • Secondary skin infections from scratching.
  • Insomnia.
  • Psychological distress: shame and social isolation can be significant.

What to look for in the home?

This is a job for professionals: advise your patient to get their home thoroughly checked for evidence of bedbugs if you suspect they have bedbug bites. Bedbug traps might help identify a low-level infestation but will never eradicate them fully.

Signs might include:

  • Dark faecal spots in mattress crevices.
  • Visible exoskeletons in crevices (common locations listed above).
  • A musty sweet smell.

Management

Your patient Their home
  • Rash is usually self-limiting over 1–2 weeks.
  • Keep skin clean and avoid scratching.
  • Topical hydrocortisone or antihistamines can be advised if pruritus is a problem.
  • Ask about and support any mental health effects.
  • Look for and manage any secondary skin infections (see Impetigo and Cellulitis articles).
  • Specialist eradication needed.
  • Vacuum: must be a bag vacuum, and the bag must be removed and sealed in a plastic bag and disposed of immediately.
  • Wash textiles at 60° C, or freeze at -20° C for at least 2 hours (domestic freezers will not be adequate for this).
  • Steam mattresses and furniture.
  • Travellers should decontaminate belongings and luggage on returning home.
  • Bedbugs are largely resistant to insecticides. Do not use 'bug bomb' insect-fogging devices as they contribute to this.

Bedbugs

  • Painless, itchy maculo-papular erythematous bites in clusters on exposed skin should prompt us to consider bedbugs: ask your patient to check their home for signs of infestation.
  • Complications can include psychological distress, insomnia and skin infections.
  • Commercial insecticides are largely ineffective: advise your patient they need professional eradication.