Anaphylactic shock induced by paracetamol.

A 46 year old woman had adverse reactions to paracetamol. Oral challenge tests with the drug showed that the reactions were dose-dependent and they reproduced similar symptoms consisting of vomiting, diarrhoea, pruritus, skin rashes, facial oedema, dyspnoea and hypotension. There was a marked increase in blood histamine but the complement components C3 and C4 remained at normal levels. Treatment with epinephrine and moderate doses of betamethasone brought fast recovery without any further complication.