In the early days of the New York COVID-19 outbreak, as March turned to April, hematologist Jeffrey Laurence was called to consult on the case of a 32-year-old bodybuilder. Nurses had noticed an odd rash on his buttocks, “as if you had kind of peeled away the skin layer and were seeing what blood vessels look like on his bottom,” recalls Laurence, who works at Weill Cornell Medicine in New York City. The vessels were outlined so clearly because the blood inside was coagulating, almost jelly-like.
Within a couple of weeks, Laurence observed several similar, striking cases — making some of the earliest observations that the blood-clotting process could go horribly awry in severe instances of COVID-19. Researchers and clinicians are working to understand why, and trying medications to tamp down the clotting or the
