title: Allergic contact dermatitis from ethyl chloride and benzocaine.
abstract: Ethyl chloride (EC) or chloroethane (C2H5Cl) is a volatile halogenated hydrocarbon. Reports of contact sensitivity to this gas are infrequent considering its widespread use as a local anesthetic, and it may have a relatively low sensitization potential. Benzocaine is another local anesthetic derivative of the ethyl ester of para-aminobenzoic acid, previously reported as a causative agent of delayed hypersensitivity reactions. We present a patient who developed a generalized itching dermatitis after the application of a medical aerosol containing EC, as well as facial angioedema and tongue swelling after the local application of benzocaine. Patch-test results were positive for EC "as is" (++), benzocaine 5% in petrolatum (++), and caine mix (+++) at 96 hours (day 4). The possibility of cross-sensitization between both drugs would not have been chemically plausible. We report the first published clinical case of contact allergic dermatitis from two chemically unrelated local anesthetics (EC and benzocaine) in the same patient.
authors: Unidad de Alergología, Complejo Hospitalario de Jaén, 23007 Jaén, Spain. juanluanguita@telefonica.net
authors: Juan Luis Anguita
authors: JL
authors: Carazo
authors: Blanca Sáenz de San Pedro
authors: BS
authors: Morera
authors: Luis Palacios
authors: LP
authors: Colom
authors: José Manuel
authors: JM
authors: Gálvez Lozano
mesh_terms: D000336:Aerosols; D000779:Anesthetics, Local / Q000009:adverse effects*; D001566:Benzocaine / Q000009:adverse effects*; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000209:etiology*; D005018:Ethyl Chloride / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008875:Middle Aged; D010328:Patch Tests
chemical_list: D000336:Aerosols; D000779:Anesthetics, Local; D005018:Ethyl Chloride; D001566:Benzocaine