Yeast allergy symptoms Gastrointestinal issues such as diarrhea, bloating, gas, and stomach pain are possible symptoms. Some persons experience a rash or other sort of skin irritation as a result of the medication. People who are allergic to yeast have a severe reaction known as anaphylaxis. Anaphylaxis can be fatal if not treated promptly. Yeast is a fungus that grows on all bread. When you eat bread with yeast in it, such as bagels, rolls, and pizza, the fungus grows and causes problems for some people. This is called yeast sensitivity or yeast intolerance. Not everyone who eats yeast products will develop symptoms, but those who do may experience any of the following: Gas, stomach cramps, and diarrhea. These are common symptoms of a yeast allergy. In fact, these are often used to diagnose the condition. It is important to identify allergies before they become serious problems. Yeast allergies can be diagnosed by seeing your doctor or nurse practitioner. They will conduct a physical examination of your body and ask you about your lifestyle and diet. They may also perform tests to determine whether you are sensitive to yeast. The best way to control yeast sensitivity or intolerance is not to eat foods containing yeast. Cut out sugar and processed foods since these items contain many additives and preservatives which cause yeast to grow.