ABSTRACT
A case series of 4 patients allergic to diclofenac was reported in 2016. Patch testing showed positive reactions to gel and to diclofenac sodium 1% pet. In the period 1996-2001, in 2 hospitals in Spain, 3 patients were diagnosed with contact allergy and with zero photocontact allergy to diclofenac. In a multicenter study in Italy, performed in the period 1985-1994, 3 photopatch test reactions were seen to diclofenac; the patch test concentration used was not mentioned and relevance was not specified. Patch tests with diclofenac were negative, but both patients had positive photopatch tests, one to 5% and 10% pet. Patch and photopatch tests were negative to the plain patch tests but positive to photopatch tests with the gel 'as is' and diclofenac 1% pet. Patch tests were negative, but photopatch tests positive to the gel and its ingredient diclofenac 1% alc. Spanish authors considered a positive patch test reaction to diclofenac cream to be cross-reaction of diclofenac to indomethacin.
