When a yeast cell enters the lung, it can act as a bystander, enjoying the environment and offering no ill will. But over time, the yeast may gain a stronghold and begin a change from a cellular appearance to one that forms branches, also known as hyphae. When this happens, trouble is soon to follow. The immune system cannot deal with these larger structures and attempt to find other ways to combat the growing colony. Unfortunately, this leads to a response akin to an allergy leaving the person with even more respiratory struggles. Without proper treatment, the process can end up being life-threatening.