Derm Dx: Erythematous, Itchy Papules on the Extremities and Trunk - Clinical Advisor

Derm Dx: Erythematous, Itchy Papules on the Extremities and Trunk

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A 27-year-old man presents with acute onset of an itchy rash on the extremities and trunk. He is in good health and does not take any oral medications or recreational drugs. He has recently returned from a work-related trip where he drove to several different states. Examination reveals numerous erythematous papules on the extremities and trunk.

Which of the following is the most likely diagnosis?

Bedbugs belong to the family Cimicidae and are frequently referred to as cimicids.1 The 2 most common species that prey on humans are C lectularius and C hemipterus. Bedbugs feed on their hosts throughout the night, targeting exposed areas of...

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Bedbugs belong to the family Cimicidae and are frequently referred to as cimicids.1 The 2 most common species that prey on humans are C lectularius and C hemipterus. Bedbugs feed on their hosts throughout the night, targeting exposed areas of skin such as the arms, shoulders, and legs.2 After these parasites finish feeding, they relocate to hide in places where their host rests, such as a bed or couch.1 The bedbug is a flat, reddish-brown, and oval-shaped insect that becomes elongated and more red in color after feeding.1

When bedbugs bite their host, they inject an anesthetic mixed with saliva that results in pruritic and erythematous skin lesions.3 When ≥3 bites appear in a straight line, a pattern known as “breakfast, lunch, and dinner,” this is highly suggestive of infestation with bedbugs.4 This pattern may result from sudden movement of the host, which causes the bedbug to detach and reattach at a nearby site during feeding.4

Once diagnosis is confirmed, symptomatic treatment and patient education is warranted. Topical steroids are considered first-line therapy. Oral antihistamines may provide systemic relief, and severe cases may warrant intramuscular steroids. Bedbugs are eradicated by heat; therefore, clothing and bedding should be washed in hot water. Steam-cleaning or treatment of garments with insecticides is usually necessary for complete elimination.5 With proper treatment of the host and elimination of bedbugs, lesions typically resolve in 1 week.3

Julie Grandinetti, PA-C, is on staff at Mount Sinai Hospital in the Bronx, New York, and Stephen Schleicher, MD, is director of the DermDox Center for Dermatology, as well as an associate professor of medicine at Commonwealth Medical College and a clinical instructor of dermatology at Arcadia University and Kings College.

References

1. Williams K., Willis M. Bedbugs in the 21st Century: The reemergence of an old foe. Laboratory Medicine. 2012;43(5):141-148.

2. Doggett SL, Russell R. Bed bugs- What the GP Needs to Know. Aust Fam Physician. 2009;38(11):880-884.

3. Bemardeschi C, Le Cleach L, Delaunay P, Chosidow O. Bed bug infestation. BMJ. 2013;346:30-33.

4. Peres G, Yugar LBT, Haddad Junior V.  Breakfast, lunch, and dinner sign: a hallmark of flea and bedbug bites. An Bras Dermatol. 2018;93(5): 759-760.

5. Davis RF, Johnston GA, Sladden MJ Recognition and management of common ectoparasitic diseases in travelers. Am J Clin Dermatol. 2009;10(1):1-8.

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