0.66 Images of memorable cases: case 73

73. scabies

A skin biopsy shortly after admission showed nonspecific findings. A repeat biopsy five weeks later uncovered numerous Sarcoptes scabiei mites. After several courses of scabicidal therapy, the rash resolved. But the story didn’t end there.

Thirty-five hospital workers acquired scabies from this patient. The incubation period for those virgin cases ranged from five to11 days, a distinctly shorter time frame than the 10 days to a month or more cited in textbooks. Many other personnel who came in contact with this patientnever got the disease, including her personal physician, who examined her twice daily. A consultant, however, who had had scabies as a medical student, acquiredit from this patient and became symptomatic 24 hours after examining her.

Observations in this case teach several lessons: 1) in some patients, diagnosing scabies requires more than one attempt; 2)susceptibility to scabies varies considerably; 3) the incubation period for virgin cases can be much shorter than what the textbooks cite; 4) in cases ofrepeat infection, the incubation period is only 24 to 72 hours; and 5) any unexplained, persistent, intensely pruritic skin rash should be considered asscabies until proved otherwise.