Multiple Chemical Sensitivity: An Italian Prevalence Multicentric Survey

Giovanni Genovese¹Caterina Elisabetta Rizzo^1*Antonio Mistretta²Francesco Leonforte³Raffaele Squeri¹Carlo Signorelli⁴Cristina Genovese^2*

• ¹Università degli Studi Messina, Department of Biomedical, Dental and Morphological and Functional Imaging Sciences, Italy
• ²Universita degli Studi di Catania Dipartimento di Scienze Mediche Chirurgiche e Tecnologie Avanzate GF Ingrassia, Catania, Italy
• ³Azienda Ospedaliero Universitaria Policlinico G Rodolico San Marco, Catania, Italy
• ⁴Universita Vita Salute San Raffaele, Milan, Italy

Background: Multiple Chemical Sensitivity (MCS) is a multisystem environmental disorder triggered by exposure to chemical agents at concentrations below toxicological thresholds. Despite controversy surrounding its classification, MCS is increasingly recognized for its significant impact on health and quality of life. This study aims to evaluate the prevalence, symptomatology, and risk factors associated with MCS in the general population, using the Quick Environmental Exposure and Sensitivity Inventory (QEESI) as a diagnostic tool. Methods: A multicenter retrospective study was conducted on 494 adults. Participants completed the QEESI questionnaire, and data were analyzed for clinical correlations, laboratory findings, environmental exposures, and socio-demographic characteristics. Results: The analysis revealed that 5.7% of the population exhibited symptoms compatible with MCS. Notably, 1.4% reported changes in work or residence due to receiving an allergic or rheumatologic diagnosis. Strong associations were identified between MCS-related symptoms and exposures such as food preservatives, colorings, Wi-Fi, and chemicals the condition: Symptom severity scoring was high in 15.8% of participants, while chemical intolerance was high in 86.4%. A total of 15.5% underwent further diagnostic evaluations, with 21.4% agents. Statistical analysis highlighted correlations between MCS symptom severity and variables such as chemical intolerance, hyperosmia, hypergeusia, and dermatological reactions. Risk profiling classified 10.73% of participants as highly suggestive of MCS. Conclusions: This study confirms the presence of MCS symptoms in 5.7% of the population and highlights that a significant portion, with 10.73% being classified as "very suggestive" and 40.4% as "moderately suggestive" of the condition, may be vulnerable to chemical exposures. The results support the need for standardized diagnostic protocols and multidisciplinary approaches to management.