Scabies: Refine your exam, avoid these diagnostic pitfalls
Nearly half of all infections are missed when first examined. Attentiveness to specific details, particularly in 3 common scenarios, can help ensure an accurate Dx.
VIDEO shows scabies mite in motion
PRACTICE RECOMMENDATIONS
› Consider scabies with any severe pruritic eruption. Conduct a thorough physical exam, preferably with a dermatoscope, for burrows in the webs and sides of fingers, proximal palm, and wrists. A
› Consider scabies in all patients—especially the immunocompromised—who have distal white or yellow thick, scaly, or crusted plaques. C
› Include scabies in the differential when patients present with smooth nodules of the genitals or pruritic smooth papules and plaques in other locations. A
Strength of recommendation (SOR)
A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series
2. A patient with distal white or yellow, thick, scaly, or crusted plaques is often thought to have psoriasis or dermatitis. But scabies should be included in the differential diagnosis. In particular, worsening thick, scaly plaques in an immunocompromised patient should prompt consideration of scabies.
3. Smooth nodules of the genitals in males, or pruritic smooth papules and plaques in other locations, should lead to the consideration of scabies. These presentations can be mistaken for lichen planus, folliculitis, papular urticaria, insect bites, or atopic dermatitis.
Due to the limited amount of mite burrows early in the disease process of scabies, and the gross similarities to a patient with dermatitis with skin excoriations, a thorough exam is needed—one that goes beyond the traditional web spaces and includes hidden/atypical locations such as margins of the feet and hands, the scalp, and neck creases. Careful and deliberate inspection for burrows is critical before ruling out the diagnosis.
CORRESPONDENCE
Art Papier, MD, 400 Red Creek Drive, Suite 200, Rochester, NY 14623; art_papier@urmc.rochester.edu.
ACKNOWLEDGEMENT
We thank Angela Delacenserie, MA, for reviewing the manuscript and providing editing suggestions.
