Investigation of the Frequency of Hereditary Hyper Alpha-tryptasemia in Patients With Elevated Basal Tryptasemia

The aim of the study is to assess the number of patients with elevated blood tryptase for whom this elevation could be linked to a hereditary alpha-tryptase secretion abnormality or hyper-alpha-tryptasemia. This information will enable to better optimize the management and follow-up of patients who have experienced hypersensitivity reactions and have elevated basal blood tryptase levels. The patients will be offered the opportunity to take part in the study. If they consent to participate, they will be tested for hereditary hyper-alpha-tryptasemia. A blood sampling will be performed in the center. A few weeks after, the patient will be informed about the blood sample result during a medical consultation organized in the center.