Permanent cosmetic implants could cause allergic reactions such as arthritis, according to a report published in the Archives of Dermatology journal.
Doctors have reported that some patients developed problems over a year after the fillers or implants were placed.
The report said that the safety of polyalkylimide implant gels is questionable.
Dr Jaume Alljotas-Reig of the Vall d’Hebron University Hospital and Autonomous University of Barcelona said that both doctors and patients needed to be aware of delayed reactions.
The team examined 25 patients who had adverse reactions a year or more after having filler implants.