Cherry-red discoloration

Carbon monoxide is a toxic, colorless, odourless, tasteless and non-irritant gas that is produced during incomplete combustion, for example, in burning a fuel (e.g. wood) within an enclosed space that has a limited amount of oxygen. Carbon monoxide binds to hemoglobin - the oxygen-transporting protein found in red blood cells - with an affinity of about 230 times that of oxygen forming carboxyhemoglobin, thereby reducing oxygen supply to tissues.

The bright cherry red carboxyhemoglobin discolours the skin and mucous membranes – cherry-red discoloration. However, this discoloration is rare in carbon monoxide poisoning – in one study, 1 of 100 patients with carbon monoxide poisoning had the discoloration; there is also disagreement regarding which color exactly constitutes cherry-red.

Sources of carbon monoxide include fires, furnaces, vehicle exhausts, lawn mowers, etc.; carbon monoxide poisoning is one of the commonest forms of poisoning worldwide.

Reference:

Simini B: Cherry-red discolouration in carbon monoxide poisoning. Lancet, 1998 352(9134):1154 Go to reference

Carbon monoxide

 Image from Wikimedia Commons