A long-lasting allergic patch test reaction (LLAPTR) is generally defined as a positive patch test reaction that persists for weeks or months, at least 2 weeks after application of the allergen. Several allergens, including gold sodium thiosulfate, have been reported as causes of LLAPTR, however, it has never been described in the Korean dermatologic literature. We report a case of LLAPTR to Cl+Me-Isothiazolinone (Kathon CG) and p-tert-butylphenol formaldehyde resin (PTBP-FR) in a 45-year-old woman with suspected allergic contact dermatitis.
Allergens ; Dermatitis, Allergic Contact ; Female ; Formaldehyde ; Gold Sodium Thiosulfate ; Humans ; Middle Aged ; Patch Tests ; Resins, Synthetic ; Thiazoles ; Thiosulfates

BACKGROUND: The oral mucosa is constantly exposed to several irritants and allergens including dental materials, but the role of contact allergy in oral disease is obscure. OBJECTIVE: To analyze positive patch test results in patients with oral diseases and evaluate the clinical relevance of oral diseases with contact allergy to dental materials. METHODS: We retrospectively analyzed patch test results with dental screening series in 44 patients with oral disease from 2004~2011. RESULTS: Oral diseases included oral lichen planus (54.5%), cheilitis (27.3%), burning mouth syndrome (9.1%), and others (9.1%). Thirty-one of 44 patients (70.5%) had positive reactions to one or more allergens. The most commonly detected allergens were gold sodium thiosulfate (25.0%) and nickel sulfate (25.0%), followed by potassium dichromate (22.7%), cobalt (15.9%), palladium (6.8%), mercury (4.5%), copper (4.5%), and methylhydroquinone (4.5%). Six of 24 patients with oral lichen planus had a symptom in areas adjacent to dental materials and positive patch test reactions to allergens contained in the suspected dental materials. CONCLUSION: Patch tests with dental screening series are worth considering for oral diseases, especially for oral lichen planus.
Allergens ; Burning Mouth Syndrome ; Cheilitis ; Cobalt ; Copper ; Dental Materials ; Gold Sodium Thiosulfate ; Humans ; Hypersensitivity ; Irritants ; Lichen Planus, Oral ; Mass Screening* ; Mouth Mucosa ; Nickel ; Palladium ; Patch Tests* ; Potassium Dichromate ; Retrospective Studies