Drug-induced hypersensitivity syndrome in internal medicine: diagnostic and therapeutic traps. Eight observations

PURPOSE: Drug-induced hypersensitivity syndrome (DIHS) is an acute and severe drug reaction. Manifestations include severe skin lesions, fever, nodal enlargement, blood eosinophilia and multisystemic involvement. The severe systemic manifestations of DIHS are responsible for a 10% mortality rate. The pertinence of corticosteroid therapy is discussed. METHODS: The authors report eight retrospective cases of DIHS obtained from the PMSI (Programme de Médicalisatiopn des Systèmes d'Information) between November 1991 and November 1998. RESULTS: The series consisted of five male and three female patients (mean age: 52.6 years; range: 23-83 years). The interval between the introduction of the drug and the onset of the reaction varied from two to eight weeks. Due to severe systemic manifestations, three patients were given corticosteroid therapy. Healing of skin and systemic disorders resolved with a mean delay of 4.4 weeks (range: 1 to 56 weeks). CONCLUSION: DIHS can be a diagnostic trap, as there are no diagnostic criteria for DIHS. Only the association of multiple arguments such as the time to the occurrence of symptoms, clinical similarity to many infectious illnesses, hypereosinophilia, atypical lymphocytosis, etc. may help guide diagnosis. DIHS can also be a therapeutic trap, as prompt withdrawal of the offending drug is essential to minimize morbidity. Although still controversial in the literature, the pertinence of corticosteroid therapy may be discussed in case of severe systemic effects. Patch testing can be a valuable tool to determine the responsibility of a drug; however it proves to be useful only when positive.