title: Colloidal silica-induced hypersensitivity: myth or reality.
abstract: BACKGROUND
  Many excipients have been reported to induce drug hypersensitivity (e.g. colouring additives, preservatives). Colloidal silica has never been reported to induce drug hypersensitivity reactions.
  
  
  METHODS
  We report herein a 40-year-old patient who developed a skin eruption 2 days after Voltarene(®) (diclofenac) intake, confirmed by a positive patch test. Investigation of cross reactivity, assessed by patch testing to other non steroidal anti-inflammatory drugs, have showed a positive reaction only to piroxicam (Piroxen(®)), ketoprofen (Oki(®)) and indometacin (Indocid(®)). A hypersensivity to colloidal silica, a common excipient, was suspected. A patch test to this compound was performed showing a positive reaction.
  
  
  CONCLUSIONS
  Colloidal silica, a compound widely used in drug manufacturing, could be another culprit excipient in inducing skin hypersensitivity reactions.
authors.affiliation: Pharmacology department, Faculty of Medicine, Monastir, Tunisia. benfredj.nadia@gmail.com.
authors.forename: Nadia
authors.initials: N
authors.lastname: Ben Fredj
authors.affiliation: Pharmacology department, Faculty of Medicine, Monastir, Tunisia.
authors.forename: Najeh
authors.initials: N
authors.lastname: Ben Fadhel
authors.affiliation: Pharmacology department, Faculty of Medicine, Monastir, Tunisia.
authors.forename: Amel
authors.initials: A
authors.lastname: Chaabane
authors.affiliation: Pharmacology department, Faculty of Medicine, Monastir, Tunisia.
authors.forename: Zohra
authors.initials: Z
authors.lastname: Chadly
authors.affiliation: Pharmacology department, Faculty of Medicine, Monastir, Tunisia.
authors.forename: Haifa
authors.initials: H
authors.lastname: Ben Romdhane
authors.affiliation: Pharmacology department, Faculty of Medicine, Monastir, Tunisia.
authors.forename: Abderrazzek
authors.initials: A
authors.lastname: Boughattas
authors.affiliation: Pharmacology department, Faculty of Medicine, Monastir, Tunisia.
authors.forename: Karim
authors.initials: K
authors.lastname: Aouam
mesh_terms: D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects* / Q000737:chemistry; D004008:Diclofenac / Q000009:adverse effects* / Q000737:chemistry; D004339:Drug Compounding; D003875:Drug Eruptions / Q000175:diagnosis / Q000209:etiology*; D005079:Excipients / Q000009:adverse effects* / Q000737:chemistry; D006801:Humans; D008297:Male; D010328:Patch Tests; D011237:Predictive Value of Tests; D012307:Risk Factors; D012822:Silicon Dioxide / Q000009:adverse effects* / Q000737:chemistry; D012867:Skin / Q000187:drug effects* / Q000473:pathology
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D005079:Excipients; D004008:Diclofenac; D012822:Silicon Dioxide
keywords: Colloidal silica; Drug hypersensitivity reaction; Patch test