Allergic contact cheilitis due to effervescent dental cleanser: combined responsibilities of the allergen persulfate and prosthesis porosity.

A 55-year-old man with a dental prosthesis for 3 years had had a chronic relapsing cheilitis for more than 1 year. He was patch tested with the European standard series, his own topicals, and the dental cleanser at 10% pet. A relevant positive reaction ++ was found to the cleansing agent, which contained 20% potassium persulfate. The breakdown of the test confirmed sensitivity to this agent and to ammonium persulfate, both positive (++) at 2.5% pet. The patient was free of symptoms after he had avoided the cleanser. Subsequent chemical investigations performed with a fragment of a used dental prosthesis revealed strong adsorption of persulfate, both on the resin and on the dental tartar. Cleansing agents, adsorbed on tartar and porous resins of worn dental prostheses, should be considered as potential sensitizers and consequently patch tested on such patients with chronic cheilitis.