Thursday, July 30, 2026

W49.01 (Hair causing external constriction) reads like a joke and is anything but. It is the code for hair tourniquet syndrome - a single strand wrapped around an infant's toe, tightening as it dries until it cuts down to bone. What makes it a great coding lesson is that the specificity is clinical, not bureaucratic: hair dissolves in depilatory cream and thread does not, so W49.01 versus W49.02 tracks a real fork in treatment.