D2.530 - Digital patient-reported data uncover key clinical features of mastocytosis: insights from the MASTHAVE App

Mastocytosis is a rare and heterogeneous disease characterized by a broad spectrum of symptoms and multiple organ involvement. In routine care, symptom burden, triggers, and diagnostic findings are often incompletely captured. The MASTHAVE® app (Fig.1) was developed as a digital tool to enable real-time, patient-driven documentation on key findings related to mastocytosis.

First launched in June 2024, the MASTHAVE® app is currently available in seven countries: Germany, the United States, Belgium, Austria, the Netherlands, Spain, and Italy. 

As of 18 December 2025, the MASTHAVE® app had been downloaded 1,350 times, resulting in 628 analyzable datasets. The majority of users were female (76.4%), with a median age of 50 years (IQR 40–59) and a median age at disease onset of 30 years (IQR 18–43). Commonly reported diagnostic evaluations included serum tryptase measurement (68.5%) and abdominal ultrasound (66.9%), followed by bone density assessment (60.3%), KIT mutation analysis (50.8%), and bone marrow biopsy (50.5%). Osteopenia, osteoporosis, and spontaneous fractures were reported by 29.6%, 26.3%, and 10.8% of users, respectively. Hepatomegaly, splenomegaly, and lymphadenopathy were reported by 15.3%, 12.3%, and 5.3%. A history of anaphylaxis was mentioned by 46.2% of users. The most frequently described symptoms were fatigue (77.1%), pruritus (75.3%), bloating (69.4%), flushing (68.0%), and joint pain (62.9%). Cutaneous involvement was more commonly reported by male than by female (70.6% vs. 57.2%). Stress, temperature changes, and food or alcohol were the most frequently reported triggers. Stress was predominantly associated with neurological symptoms and flushing, food and alcohol with gastrointestinal symptoms, and temperature changes and physical activity with pruritus.

Real-world data from the MASTHAVE® app demonstrate a high symptom burden and substantial disease heterogeneity in mastocytosis, underscoring the value of digital patient-reported data for improved disease characterization and personalized management.