Don't forget syphilis.

INTRODUCTION THE incidence of primary and secondary syphilis has shown a steady increase in Great Britain in the last decade, from a figure of 1,162 in 1970 to 1,543 in 1979 for England and Wales. The incidence in Northern Ireland has been somewhat more sporadic (Figure) but we have found, in common with our colleagues in the United Kingdom,' a tendency to forget these conditions in arriving at a differential diagnosis. The following cases were collected at the Genito-Urinary Medicine Department of the Royal Victoria Hospital, Belfast between 1978-80 and illustrate some situations where misdiagnosis can easily be made. 60* FIGURE I