Impact of Delayed Diagnosis on Quality of Life in Patients with Mast Cell Activation Syndrome

–Mast Cell Activation Syndrome (MCAS) is a complex disorder characterized by recurrent episodes of multisystem symptoms due to inappropriate mast cell mediator release. Patients frequently face prolonged diagnostic delays, often spanning years, as symptoms mimic those of other chronic conditions. The impact of such delays on patient quality of life remains underexplored. This study aims to evaluate the relationship between delayed diagnosis and patient-reported quality of life outcomes in MCAS. Using data collected from patient-reported surveys distributed through The Mast Cell Disease Society, we analyzed diagnostic timelines, comorbidities, and validated quality of life indicators, including physical health, mental health, fatigue, pain, sleep disturbance, and cognitive functioning. Patients were stratified into early (<2 years from symptom onset) and late (≥2 years) diagnosis groups. Preliminary findings suggest that patients with delayed diagnosis report poorer outcomes across physical, emotional, and cognitive domains, with increased fatigue, pain interference, and brain fog compared to those diagnosed earlier. These results underscore the clinical and psychosocial burden of diagnostic delay in MCAS and highlight the urgent need for improved awareness, timely recognition, and earlier intervention strategies.