Photosensitivity induced by fibric acid derivatives and its relation to photocontact dermatitis to ketoprofen.

BACKGROUND: Photosensitivity reactions to fibric acid derivatives are not well understood and have been rarely reported. OBJECTIVE: The aim of this study was to describe two cases of photosensitivity, one induced by fenofibrate and one by bezafibrate; to study the in vivo photosensitizing potential of these drugs; and to evaluate the possibility of cross-reactivity between fenofibrate and ketoprofen. METHODS: Patch and photopatch tests with fibric acid derivatives and ketoprofen were performed in the patients, in 12 normal volunteers, and in 7 patients with photopatch-proven photocontact dermatitis to ketoprofen. Phototesting studies were performed both while the patients were taking the drugs and after withdrawal of them, as well as in a group of 18 hyperlipemic volunteers without history of photosensitivity who were taking therapeutic doses of fenofibrate or bezafibrate for 2 to 3 months. RESULTS: Positive photopatch test responses to ketoprofen and to fenofibrate were obtained only in the first patient, who also had a weaker positive ordinary patch test response to the latter. Five patients photosensitized to ketoprofen also had a positive patch test to fenofibrate. Phototesting studies were abnormal in both patients but normal in all volunteers. CONCLUSION: An association between systemic photosensitivity to fenofibrate and photocontact sensitivity to ketoprofen seems to exist. The structural similarities of these chemicals favor cross-reactivity.

Oxicam-induced photosensitivity. Patch and photopatch testing studies with tenoxicam and piroxicam photoproducts in normal subjects and in piroxicam-droxicam photosensitive patients.

BACKGROUND: The mechanism of piroxicam-induced photosensitivity is unknown. It was first attributed to metabolites of the drug produced in vivo but further photochemical studies disclosed that piroxicam was not stable to light, forming at least two photoproducts. Photosensitivity reactions to droxicam and tenoxicam have been not reported. OBJECTIVE: The aim of this study was to determine whether piroxicam photoproducts contribute to the light reactions induced by this drug, to describe a case of droxicam-induced photosensitivity and to study the in vivo photosensitizing potential of tenoxicam. METHODS: Patch and photopatch tests with two major photoproducts of piroxicam, with different preparations of UVA-preirradiated piroxicam, and with low and high concentrations of tenoxicam were performed in normal volunteers and in piroxicam-photosensitive patients. Phototesting studies were also performed before and after the oral administration of tenoxicam in both groups of subjects. RESULTS: Positive patch test responses were obtained in piroxicam-photosensitive patients only with the preirradiated piroxicam preparations. Phototesting studies with tenoxicam were normal in both groups. CONCLUSION: Minor or intermediate piroxicam photoproducts are more likely to be responsible for the photosensitivity reactions induced by this drug.

[Histopathological aspects of chromium ulcers]. / Aspectos histopatológicos de las úlceras por cromo.

The authors describe two cases of "cromeholes". Both patients were working in electroplating. The pathology of these lesions demonstrate that it refers to caustic ulcers with necrosis of the epidermis and superficial dermis, with tendency to hyperplasia of neighbouring epidermis and important infiltration of the vessels and specially of the sweat glands.