Eating, handling or inhaling baker's yeast, a beneficial mold, causes allergic reactions in some people. Those with yeast allergies who ingest Saccharomyces cerevisiae, the most common baker's or brewer's yeast, can develop extensive allergy symptoms, including digestive upset. Opportunistic yeast fungi also settle on and live off of other foods, which patients may eat. Touching or inhaling yeast may cause skin or respiratory side effects. Bakers, wine makers and beer crafters, especially, risk these as well as chronic lung problems from high-level exposure to yeast.
Inflammation
Any type of contact with yeast or foods that contain it may produce side effects of itching and swelling, according to the University of Maryland Medical Center. These signs will correlate with the area in which the allergens enter the body, such as mouth itching after eating yeast, eye or nose inflammation after inhalation, and skin symptoms after direct contact. These allergy symptoms may arise immediately or within a day or two following exposure.
Respiratory Distress
Eating yeast foods may produce additional nasal side effects in some patients. The UM Medical Center includes runny and stuffy nose conditions among the symptoms of allergic reactions to yeast and other foods and molds. The Occupational and Safety Health Administration reports that frequent environmental contact with yeast can produce these symptoms and more severe difficulty breathing. Coughing, wheezing and shortness of breath may occur in people who have asthma.
Metabolic Disturbance
When respiratory and inflammatory side effects merge, some people with yeast allergies have a rare, severe allergic reaction called anaphylaxis. This state is characterized by a rapid decline in blood pressure and increased breathing problems. The UM Medical Center warns that these allergy symptoms should prompt an emergency call for medical help. Additional health effects such as dizziness, fainting and respiratory failure can quickly lead to death.
Gastrointestinal Problems
More commonly, digestive problems follow the onset of nasal and skin side effects. The UM Medical Center reports that nausea, stomach pain, cramps, vomiting and diarrhea can occur from an allergic reaction in people with yeast allergies. These symptoms usually appear within one to two hours after eating yeast foods and subside shortly thereafter.
Long-term Side Effects
Individuals whose exposure to yeast persists despite their allergy symptoms may develop chronic lung disease. People who ignore yeast allergies or who continue to work with yeast can contract hypersensitivity pneumonitis, OSHA reports. This progressive lung tissue degeneration can reach an irreversible state if contact with allergenic yeast does not end.
