Uses of Sulfites
Sulfites are chemicals commonly used as preservatives for various foods and medications. Sulfites come in different chemical forms: sodium sulfite, sodium metabisulfite, sodium bisulfite, potassium bisulfite, and potassium metabisulfite.
When added to food, sulfites have the ability to slow down bacterial growth, giving the food longer shelf-life. Sulfites can also enhance the flavor and freshness of certain foods such as vegetables and fruits. It is because sulfites inhibit oxidation or browning of fresh vegetables and fruits. The browning of seafood can also be prevented by the addition of sulfites.
Sulfites are also naturally occurring compounds in some foods including fermented beverages (e.g. beer and wine), vegetables and fruit juices. Sulfites are also found in nature: in soil, water, air, and living organisms.
Sulfites are added to some medications for their anti-browning and antioxidant properties.
Prevalence of Sulfite Allergy
According to the Food and Drug Administration (FDA), it is estimated that 1% of the American population is allergic to sulfite. The agency also estimated that 5% of Americans with asthma is allergic to sulfite. It is not yet clear why some people are allergic to sulfite while others are not. The mechanism of the allergic reaction is also not yet known. Allergy to sulfite begins at any period in a person’s life.
Sulfite Allergy Signs and Symptoms
The signs and symptoms of sulfite allergy can occur immediately after consuming foods/drinks containing significant amount of sulfite or after inhalation of fumes containing sulfite. In some cases, the symptoms occur after minutes or hours of exposure to foods and fumes containing sulfites compounds.
The respiratory symptoms of sulfite allergy include cough, breathing problems or difficulties, sneezing, and runny nose.
Sulfite allergy causes nausea, vomiting, indigestion, stomach upset, abdominal pain, constipation, and vomiting.
Observable symptoms in the skin include skin rashes, itching, flushing, hives or swelling (edema).
Itching or burning sensation can also be felt in the eyes.
Anaphylactic shock is considered the worst symptom of sulfite allergy. Anaphylactic shock involves a dangerous drop in blood pressure, serious breathing problems, loss of consciousness, or coma.
Tests for Sulfite Allergy
The main problem in diagnosing sulfite allergy is the similarity of its symptoms to other allergies like strawberry , peanut, and mold allergy. In diagnosing sulfite allergy, the help of a professional allergist is needed. The allergist will perform some tests to a patient suspected with having sulfite allergy.
Skin test is a common test in diagnosing allergy to a certain substance. In this test, a small sample of sulfite is used to prick or scratch the skin of the patient. If rush, hive, or swelling appear in the skin, the patient may be allergic to sulfite.
With the supervision of a highly experienced physician, an allergist can perform an oral metabisulfite challenge to a patient. The procedure involves giving the patient increasing amounts of metabisulfites to swallow. The physician will then monitor the lung function and other vital signs of the patient. If significant decline in lung function and abnormal changes in vital signs occur then the patient is considered allergic to sulfite.
Treatments for Sulfite Allergy
A person having trouble with sulfite allergy symptoms should seek medical treatment from healthcare providers. Anaphylactic shock is a serious condition that needs immediate medical attention.
Injectable epinephrine is given to patients with severe allergic reactions and anaphylaxis. Asthmatic patients need the use of inhaled bronchodilator solutions that do not contain sulfites.
For safety purposes, people with severe sulfite allergy are advised to carry injectable epinephrine which can be used anytime allergic reactions occur. Take note that sulfites are not only found in food, they are found in the environment ready to cause trouble. If you have extreme allergy to sulfites, injectable epinephrines can save your life!
Prevention of Sulfite Allergy Symptoms
Prevention is still better than cure. Be knowledgeable on foods and medications that contain significant amount of sulfites. Read the labels of food products to know if they contain sulfites and how much. The FDA gave a mandate instructing food manufacturers to label foods containing more than 10 ppm of sulfites. Foods containing less than 10 ppm of sulfites have not been shown to cause allergic responses even in people allergic to sulfites.
Since the FDA banned the application of sulfites to fresh fruits and vegetables in restaurants, there has been a big reduction of cases involving accidental ingestion of sulfites. However, there are still restaurants serving unlabeled sulfite-containing foods.