CD12 Citalopram-induced drug reaction with eosinophilia and systemic reaction confirmed by patch testing

Abstract A 46-year-old man was referred for investigation of an acute widespread rash and fever that started 4 weeks after commencing citalopram. Clinical histological features were consistent with drug reaction eosinophilia systemic (DRESS). He not on any other medication, had no known allergies previously taken a selective serotonin reuptake inhibitor (SSRI). Six months resolution, he patch tested to the extended British Baseline Series citalopram (crushed tablet in 50% petrolatum). Readings days 2 (D2) (D4) positive (D2 ++ D4 +++). To investigate possible crossreactivity, subsequently fluoxetine, paroxetine sertraline tablets petrolatum), which showed [D2 (–) (+)]. Patch tests negative irritancy normal volunteer. SSRIs are extensively increasingly used depression mental health problems; 45 000 UK prescriptions issued last financial year. Despite such use, cutaneous adverse reactions (CADRs) appear be rare. From 1998 2022, Medicines Healthcare products Regulatory Agency recorded 16 586 citalopram, only 1077 (6.5%) cutaneous. Various rashes have been reported arise from SSRI treatment, ranging maculopapular eruptions toxic epidermolysis necrolysis/Stevens–Johnson syndrome. There isolated reports DRESS escitalopram (the S-enantiomer citalopram). our knowledge, this is first case citalopram-induced DRESS. The sensitivity specificity diagnosis delayed CADR varies according rash. We found following exanthems. Our findings highlight diagnostic role extemporaneous preparation SSRI-induced diverse chemical structures, we speculate may benefit identifying safer alternative should further treatment needed.