Bedbug Bite Reaction

Bedbug bite reactions follow feeding by Cimex lectularius (and C. hemipterus in the tropics), nocturnal blood sucking insects that live in mattress seams, bed frames, furniture and cracks. Reactions range from none to large bullae, urticaria and rarely anaphylaxis.

• Infestations are linked to travel, second hand furniture, crowding, dormitories, informal settlements and hotels.
• Bedbugs are not established vectors of disease.

Itchy erythematous papules or wheals, often in linear or clustered groups of three ("breakfast, lunch, dinner"), on exposed skin during sleep (face, neck, arms, hands, legs).

• Central haemorrhagic punctum; bullous reactions in sensitised people; onset hours to days after bites.
• Evidence in bedding: rusty or dark faecal spots, blood stains, shed skins, live bugs, sweet musty odour.
• Differential diagnosis: flea bites, mosquito bites, scabies, papular urticaria, urticaria, contact dermatitis, folliculitis, dermatitis herpetiformis, drug eruption, chickenpox.
• Complications: secondary infection (impetigo, ecthyma, cellulitis), anaemia in heavy infestation, insomnia, anxiety, allergic reactions including asthma, rarely anaphylaxis.

Clinical; confirm by finding bedbugs or faecal spots on mattress seams, bed frames and nearby furniture.

• Full blood count in prolonged heavy infestation.
• Biopsy is not needed.

Treat the skin and eradicate the infestation.

• Supportive: avoid scratching, cool compresses, wash bedding and clothing at 60 degrees Celsius for 30 minutes and dry on high heat, vacuum mattress and furniture, encase mattresses and box springs in zipped covers, seal cracks, reduce clutter, professional pest control with insecticide and heat treatment, discard badly infested items, treat all infested rooms in the household together.
• Pharmacological: hydrocortisone 1 percent or mometasone 0.1 percent cream once or twice daily for 5 to 7 days; oral cetirizine 10 mg daily; for bullous or extensive reactions prednisolone 0.5 mg/kg daily for 3 to 5 days; fusidic acid 2 percent cream three times daily or flucloxacillin 500 mg four times daily for 7 days for secondary infection. Anaphylaxis: adrenaline 0.5 mg (0.5 mL of 1 in 1000) IM into the anterolateral thigh in adults, 0.01 mg/kg in children, repeat after 5 minutes if needed.
• Procedures: none.
• Special groups: pregnancy, topical steroid and cetirizine, avoid insecticide application on skin; children, mild steroid and nail care; asthmatics, watch for exacerbation.
• Red flags: widespread urticaria with breathlessness, facial swelling, collapse, fever with spreading cellulitis, severe anaemia.
• Follow-up: review at 1 to 2 weeks; confirm eradication by repeat inspection at 2 and 4 weeks.