Let’s talk about getting better sleep with MCAS. Sleep can be a major issue when you have a complex chronic illness like Mast Cell Activation Syndrome (MCAS). Without adequate sleep you can’t function at your best, you are chronically tired, and you are prone to accidents and making mistakes. But beyond that, mast cell mediators can actually cause insomnia, excess histamine can cause sleep disturbance, and sleep deprivation can be a trigger for your MCAS symptoms. It is a self-perpetuating cycle that can lead to total misery.