Topical Provocation in Fixed Drug Eruption from Nonsteroidal Anti-Inflammatory Drugs

Abstract

Objective: Evaluate the importance of topical lesional provocation in the study of fixed drug eruption (FDE) from nonsteroidal anti-inflammatory drugs (NSAID). Patients and Results: We studied 14 patients with FDE imputed with high probability to piroxicam (8 patients), nimesulide (5) and feprazone (1). One patient with FDE from piroxicam suffered lesion reactivation after intravenous tenoxicam. The suspected drug and related compounds were patch tested on residual lesional skin and on the normal back skin. Positive results were obtained, only in affected areas, in 13 out of 14 patients (92.9%): in all cases due to feprazone and nimesulide and in 7/8 cases of FDE due to piroxicam. The 7 patients reactive to piroxicam also had positive tests to tenoxicam, and 1 out of 5 reacted to meloxicam. None reacted to thiosalicylic acid. Comments and Conclusions: Topical lesional provocation is a safe, sensible and specific complementary method for drug imputation in FDE from these NSAID, namely for nimesulide, as it reproduced a positive test in the 5 patients. In the case of FDE from piroxicam, our studies confirm cross-reactivity with tenoxicam whereas in piroxicam-induced photosensitivity tenoxicam can be used safely. In photosensitivity the responsible moiety is a UVA photoproduct of piroxicam antigenically and structurally similar to thiosalicylic acid, a moiety which is not involved in FDE.