Hypersensitivity to fluindione (Previscan®).: Positive skin patch tests

Introduction. Fluindione (Previscan((R))) is an oral anticoagulant belonging to the vitamin K antagonist class and is very widely used in France. While bleeding is a common complication, severe immunoallergic reactions are less frequent. The authors report a case of drug-induced hypersensitivity syndrome. Case report. A 75 year-old woman was hospitalized for diffuse erythematous papular rash associated with facial oedema. These symptoms appeared 3 weeks after the beginning of treatment with fluindione, allopurinol and perindopril. Laboratory tests showed hyperleukocytosis, mixed hepatitis and moderate renal failure, with the entire picture being evocative of drug-induced hypersensitivity reaction. The eruption was associated with eosinophilia, hepatic cytolysis with cholestasis, and acute renale failure. While allopurinol and perindopril were stopped definitively, fluindione was only suspended temporarily following overdosage. On reintroduction, rapid recurrence of clinical and biologic signs was observed with increased severity. The skin rash resolved completely on withdrawal of the drug. Patch tests performed later were positive for fluindione and negative for allopurinol and perindopril. Discussion. These manifestations were consistent with the diagnosis of drug-induced hypersensitivity syndrome due to fluindione. Very few cases have been described with fluindione despite widespread prescription of the treatment is in France. While there may be no skin involvement, immunoallergic signs such as fever, hepatitis and acute tubular interstitial nephritis have been described with fluindione and these may be related to this syndrome (DRESS - Drug Reaction with Eosinophilia and Systemic Symptoms). Skin patch testing, which is easily performed, can be extremely helpful in determining a causal relationship with medication.