A review of aetiological factors in erythema multiforme.

THE clinical syndrome of erythema multiforme extends from a mild rash with typical target lesions of the hands and feet to a severe illness with widespread involvement of the skin and mucous membranes as in the Stevens-Johnson syndrome (Stevens and Johnson, 1922). It has been reported to occur in association with a number of different stimuli after an interval of one to three weeks (Champion, 1972; Shelley, 1967). The list of associated factors is large and some are included on the basis of single case reports. There has, however, been no comprehensive survey demonstrating the relative importance of the various aetiological factors involved in erythema multiforme of all degrees of severity in an unselected group of patients. We therefore undertook a retrospective study of all patients newly diagnosed as having erythema multiforme over a three-year period throughout Northern Ireland.