Introduction: We present a case of a patient with a chronic carbon monoxide (CO) intoxication with facial plethora due to secondary erythrocytosis. Case details: A 22-year-old male was referred by the dermatologist to our outpatient clinic for evaluation of polycythaemia. Laboratory results showed secondary erythrocytosis. After an extensive diagnostic evaluation, we diagnosed a chronic CO intoxication (carboxyhaemoglobin (COHb) level of 21%) without apparent complaints and facial plethora as the only clinical sign. The patient denied smoking tobacco or use of illicit drugs. On inspection of his house by the fire department, a waterpipe was found in his bedroom, which he used daily, according to his father. CO measurements in the house were normal. We treated the patient with high flow oxygen and advised him to quit smoking the waterpipe. Within a few weeks, the erythrocytosis normalised. Discussion: We propose to test for the presence of an elevated COHb in all patients with a normal or high erythropoietin level. The test is not expensive and can easily be included as part of an examination, since CO intoxication has potentially disastrous consequences, and, as is illustrated with this case, chronic CO poisoning can be virtually asymptomatic. Not all individuals consider smoking a waterpipe the same as smoking or drugs, and therefore physicians need to specifically ask for its use.

Carbon monoxide poisoning, secondary polycythaemia, waterpipe
The Netherlands Journal of Medicine
Department of Internal Medicine

Raaijmakers, N.J., Bokma, A.H.F., Eggen, G.G., Prins, G., & Alsma, J. (2020). An unhealthy blush - secondary erythrocytosis due to waterpipe smoking. The Netherlands Journal of Medicine, 78(4), 202–205. Retrieved from