Sensitization to resorcinol in a prescription verrucide preparation: unusual systemic clinical features and prevalence]

BACKGROUND: Resorcinol is a rare sensitizer. In Lorraine, where it is used in high concentrations in an anti-wart ointment, this molecule has induced many cases of allergy. The purpose of this study was to describe clinical features in patients sensitized to resorcinol, to determine the incidence of sensitization in Lorraine and ascertain the occurrence of cross reactions with other phenolic pro-haptens.PATIENTS AND METHODS: The files of all patients sensitized to resorcinol were studied from 1992 to 1999. Over a 20-month period, 983 consecutive patients underwent our standard patch tests where we included resorcinol (1 p. 100 in petrolatum). Co-sensitization with other pro-haptens was studied in all sensitized patients.RESULTS: Sensitization to resorcinol was observed in 0.5 p. 100 of the 983 consecutively tested patients. Contact sensitization was found in 24 patients, who all but one had previously used the anti-wart ointment containing resorcinol. All developed contact eczema on the site of application of the ointment, with generalized urticaria (4 cases), pompholyx (1 case), and generalized papulo-vesicular rash with pompholyx (6 cases). Positive patch tests were observed with resorcinol monobenzoate (15/19 cases), pyrocatechol (7/14 cases), pyrogallol (9/19 cases), salicylaldehyde (2/17 cases), and hydroquinone (6/17 cases). Negative patch tests were observed with phenysalicylate, hexylresorcinol, or fluoresceine.CONCLUSION: Resorcinol should not be applied in high concentrations as it can provoke generalized sensitization and co-sensitization with other pro-haptens.