Sensitivity to thimerosal and photosensitivity to piroxicam

• Published in: Contact dermatitis Vol. 24; no. 3; p. 187
• Main Authors: de Castro, J L, Freitas, J P, Brandão, F M, Themido, R
• Format: Journal Article
• Language: English
• Published: England 01.03.1991
• Subjects: Adult; Benzoates - adverse effects; Benzoates - chemistry; Cross Reactions; Dermatitis, Contact - etiology; Drug Hypersensitivity - etiology; Female; Humans; Male; Patch Tests; Photosensitivity Disorders - chemically induced; Piroxicam - adverse effects; Piroxicam - chemistry; Sulfhydryl Compounds; Thimerosal - adverse effects; Thimerosal - chemistry; Ultraviolet Rays
• ISSN: 0105-1873
• DOI: 10.1111/j.1600-0536.1991.tb01696.x

17 patients allergic to thimerosal, with no previous history of photosensitivity or piroxicam ingestion, 2 patients with piroxicam-induced photosensitivity, and 10 controls were patch or photopatch tested, with 1 or more of the following: thimerosal, thiosalicylic acid, irradiated and non-irradiated solutions of piroxicam alone, L-cysteine alone and piroxicam plus L-cysteine, and piroxicam in petrolatum., The results of the tests supported the hypothesis that there are cross-reactions between thiosalicylic acid and prioxicam, a photosensitizer. The mechanism of the cross-reactions may involve photoproducts of piroxicam and L-cysteine, as patients allergic to thiosalicylic acid, who have positive photopatch tests to piroxicam, also had positive patch tests to the irradiated solution of piroxicam plus L-cysteine.