In the eldery population anti-epileptic drugs (AED) are used in epilepsy, neuralgiform pain, psychiatric disorders and behavioral problems in dementia. The prevalence of AED- treatment in the community is 1%; among nursing home residents 10%. A complex of adverse effects, known as Drug Reaction Eosinophilia and Systemic Symptoms (DRESS), is associated with several drugs, in particular AED. The incidence of DRESS syndrome is estimated between 1 in 1000 and 1 in 10000. DRESS syndrome has a high mortality rate (around 10%), primarily due to doctor's delay in recognition.

As AED-induced DRESS syndrome is rarely described in elderly patients, we describe two with dementia-related behavioural problems, treated with carbamazepine. Both patients developed severe rash, eosinophilia and fever after three weeks of administration. Patient 1 also developed anemia, diarrhoea and delirium; Patient 2 suffered from a severe edema of arms and face. Initially the clinical presentation of inflammatory and hypersensitivity symptoms was attributed to several diseases and/or medication other than carbamazepine. After recognition of DRESS by carbamazepine and stopping this drug, both patients fully recovered.

Recognition of DRESS syndrome induced by AED is difficult as the condition is rare, symptoms occur 1 to 8 weeks after start of treatment; there may be slow progression and similarity with infections and neoplastic disorders exists. Withdrawal of the offending drug is the primary treatment of the DRESS syndrome and patients relatives must be informed since the incidence of the DRESS syndrome is higher amongst first- degree relatives.