Spontaneous reporting systems (SRS) have been established to monitor drug safety problems after marketing, especially rare, but serious adverse drug reactions (ADRs). Among these are the skin disorders erythema multiforme (EM), Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). The purpose of this study has been to evaluate the data on these serious skin disorders available in a SRS. All reports concerning these diseases submitted to the Danish Committee on ADRs during the period 1968 to 1991 were reviewed according to predefined criteria. Information was often scarce, and the diagnosis of the reporter had to be accepted at face value in 28% of cases. Two hundred cases of EM, 74 of SJS and 29 of TEN were identified. More than 60% of cases were hospitalized. The diseases had a fatal outcome in six patients with TEN, three with SJS and a single patient suffering from EM.
One hundred and twenty-eight different drugs were reported as causal agents. Major drug groups involved were antibiotics (sulfamethoxazole with trimethoprim, other sulphonamides and penicillins), non-steroidal anti-inflammatory drugs, anti-epileptics and analgesics. Incidence estimates based on spontaneous reports were compared to the incidence according to the literature and data from a nationwide hospital discharge diagnosis register. The reporting fraction for EM and SJS is estimated to 10-30%, and for TEN to 25-50%0, but the validity of reports is in some cases difficult to assess owing to lack of detail.