Mast cells are mostly known for their role in allergic reactions, as well as their involvement in diseases such as mast cell activation syndrome and systemic mastocytosis. One of the secreted enzymes during the allergic reaction and mast cell degranulation is tryptase. Recently, a new syndrome, namely - hereditary alpha tryptasemia, has been defined, originating from multiple copies of TPSAB1, the alpha-tryptase encoding gene. This syndrome has characteristic symptoms as well as biochemical and genetic markers. In this article we describe the first case of alpha tryptasemia diagnosed in Israel with emphasis on the typical symptoms and the biochemical and genetic workup needed to establish the diagnosis, as well as appropriate treatment.