PATCH TEST IN THE INVESTIGATION OF CONTACT DERMATITIS

Abstract

Contact Dermatitis (CD) is a frequent inflammatory dermatosis triggered by the penetration of an exogenous agent into the skin, occurring through either irritant or allergic mechanisms. It represents the most common occupational dermatosis and has a significant impact on patients’ quality of life, being strongly associated with environmental and work-related exposures. Patch Testing (PT) is the gold standard method for diagnosing allergic contact dermatitis. Objective: To describe the clinical and epidemiological profile of patients who underwent Patch Testing at the Dermatology Outpatient Clinic of HUOP between 2023 and 2024, assessing demographic characteristics, occupational exposure, main allergens of the Latin American Battery, and the correspondence among clinical, histopathological, and immunological findings. Methods: A descriptive, cross-sectional, analytical, exploratory, and quantitative study based on electronic medical record review of all patients who underwent Patch Testing from January 2023 to December 2024. Data regarding occupation, diagnostic hypotheses, lesion distribution, clinical features, histopathology, and allergen reactivity were collected and analyzed using absolute and relative frequencies. Results: Ten patients were included; 90% were female, with a mean age of 43.8 years. Lesions primarily affected the hands and forearms (80%), followed by interdigital areas (30%), facial/periorbital regions (20%), and feet (20%). The positivity rate was 90%. The most prevalent allergens were Nickel sulfate 5.0% (50%), Caine mix III 10.0% (40%), Fragrance mix I 8.0% (30%), Methyldibromo glutaronitrile 0.5% (20%), Sodium tetrachloropalladate 3.0% (20%), and Thimerosal 0.1% (20%). Many patients demonstrated intensified or newly developed reactivity at the 96-hour reading, underscoring the relevance of extended readings. Conclusion: A high rate of sensitization was observed, consistent with data from reference centers, with a predominance of metals, fragrances, and preservatives. The findings reinforce the Patch Test as an essential diagnostic tool at HUOP and reveal a regional sensitization pattern that supports the continuation and expansion of testing within the service. This study provides valuable regional data to guide preventive measures and individualized management of patients with contact dermatitis.