371 Cutaneous Response to Patch Tests with Dermatophagoides Farinae and Dermatophagoides Pteronyssinus in Patients with Chronic Rhinitis Diego Garcia-Calderin, MD, Sandra González-Díaz, MD, PhD, Alfredo Arias-Cruz, MD, Alejandro Rojas, MD, Marisela Hernandez, MD, Claudia Gallego, MD, Karla Mejia, MD, Maricruz Calva, MD, and Luis Dominguez, MD. Regional Centre of Allergy and Clinical Immunology, University Hospital, Monterrey, Mexico; Regional allergy center, University California, San Diego U.C.S.D., Monterrey, CA, Mexico; Allergy and Clinical Immunology, University Hospital UANL, Monterrey, Mexico; CRAIC, Hospital Universitario, Monterrey, Mexico. Background: Rhinitis is characterized clinical by chronic runny nose, sneezing, nasal itching, congestion and postnasal discharge, among other symptoms. It s classified as allergic and non allergic. Skin prick testing is the principal diagnosis method for allergic rhinits. However, there is a group of patients with chronic rhinopathy that have negative skin tests, the objective of this study was to determine the cutaneous response to patch tests with Dermatophagoides farinae and Dermatophagoides pteronyssinus in patients with chronic rhinitis. Methods: It was a cross-sectional, observational and descriptive study. We included patients over 18 years old. They were divided into 3 groups; Group A patients who came for the first time with a history of chronic rhinopathy over 18 months of evolution and positive skin tests for aeroallergens; group B patients with chronic rhinitis with at least one year of evolution and negative skin tests; group C healthy volunteers. Patch test with farinae and pteronisyinnus were done in the subjects of all 3 groups, with readings at 48 and 72 hours. Results: A total of 37 patients were studied, mean age 26.1 years. Twenty two were male subjects (60%). The mean lenghtof chronic rhinophaty was 10.8 years. Six patients had positive patch test to any of the mites tested; 2 (33%) in group A, 2 (33%) in group B and 2 (33%) of the control group, but it was not statistically significant (P . 0.05). Conclusions: Although the results were not statistically significant, there were patients with chronic rhinitis wich had positive patch test for mites. This sensitization could be clinically significant for those patients.