[Clinical thinking and decision-making in practice. A patient with episodes of flushing]

A 74-year-old woman had an 8-year history of spells consisting of facial flushing and swelling, itching and erythema of the hands, rhinorrhoea and gastrointestinal complaints. The ultimate diagnosis was systemic mastocytosis without urticaria pigmentosa. In the clinical decision process the treating physicians used clinical axioms to try to establish a diagnosis, but these axioms were sometimes used inappropriately. In particular, spells accompanied by flushing inappropriately elicited a possible diagnosis of phenochromocytoma. Generalised mastocytosis can occur in the absence of urticaria pigmentosa and is probably an underestimated cause of spell-like complaints.