Prospective Single-Center Observational Study of the Allergenic Potential of Mercromina Film and Other Common Antiseptics in Patients With Contact Dermatitis. / Estudio observacional de seguridad, prospectivo y unicéntrico para determinar la capacidad alergogénica de Mercromina Film® y otros antisépticos de uso común en pacientes con dermatitis de contacto.

INTRODUCTION: Although Mercromina Film and other topical antiseptics are widely used, they are not included in the standard series recommended by the Spanish Contact Dermatitis and Skin Allergy Research Group for testing suspected allergic contact dermatitis (ACD). Furthermore, no recent studies have investigated the allergenic potential of merbromin. OBJECTIVE: To determine the allergenic potential of merbromin and compare it with that of other topical antiseptics widely used in clinical practice, including povidone-iodine, chlorhexidine, and eosin. MATERIAL AND METHODS: Prospective single-center observational safety study of 105 patients with suspected ACD seen at the dermatology department of our hospital. RESULTS: Of the 105 patients studied, 1.9% had a positive patch test to merbromin and 12.4% were sensitized to povidone-iodine. The differences in the proportion of patients with ACD to Betadine Solución Dérmica (povidone-iodine) compared with the rest of the antiseptics was statistically significant (McNemar test, P<.05). No adverse reactions were observed in any of the patients. CONCLUSIONS: Based on the patch tests conducted, Mercromina Film has very low allergenic potential. The highest allergenic potential was observed for povidone-iodine.

Mercurochrome allergy. Immediate and delayed hypersensitivity.

We describe eight patients suffering from Mercurochrome allergy. Patch and prick tests were carried out with the following organic and inorganic mercury compounds: thimerosal, Mercurochrome, phenylmercuric acetate, phenylmercuric nitrate, metallic mercury, and mercuric chloride, and with sodium fluorescein. Two patients had an anaphylactic reaction a few minutes after application of Mercurochrome. The prick tests with Mercurochrome were positive and they were negative with the other tested products. All patch tests were negative. In the other six patients, the clinical picture was local eczema, and the patch tests were all positive with Mercurochrome and the inorganic mercuric derivatives. Positive patch tests with thimerosal were found only in two patients, and only one had a positive patch test with salts of phenylmercury. In four patients, the prick test with Mercurochrome, negative in immediate reading, gave a late eczematous reaction.

Hypersensitivity to mercuric fluorescein compounds.

The mercurial compounds are known to be a common cause of allergic contact dermatitis. Immediate hypersensitivity is rarely induced by mercurial organic derivatives. However, none of the published cases showed both immediate and delayed hypersensitivity as was the case of one of our two patients. A boy and a woman experienced urticaria and anaphylaxis, respectively after topical application of Merchromine (Merbromine). We were able to demonstrate immediate hypersensitivity in both patients to mercuric fluorescein compounds by skin test and histamine liberation. In addition, the child but not the woman, showed delayed hypersensitivity to mercurial compounds.