What are the symptoms of an allergic reaction to sulfites?

The symptoms of a sulfite reaction vary from mild to life threatening. The most common symptoms are mild and involve a skin rash accompanied by redness, hives, itching, flushing, tingling, and swelling. Respiratory symptoms include difficulty breathing, wheezing, and stridor. Gastrointestinal reactions involve nausea and stomach cramps. Less common but more serious signs include low blood pressure, shock, extreme difficulty breathing and loss of consciousness.