Sulfite Allergy and Foods You Need to Avoid

A sulfite allergy is caused by exposure to sulfur-based compounds naturally found in certain foods and used in certain food preservatives and additives. This can lead to allergy symptoms like wheezing and hives and, in rare instances, a potentially life-threatening, whole-body allergy known as anaphylaxis.

Sulfite sensitivity affects roughly 4% of the U.S. population and is especially common among people with asthma who may experience a worsening of symptoms. True sulfite allergies can be treated with over-the-counter antihistamines or epinephrine for severe cases. The avoidance of sulfite-containing foods and drugs is also essential.

What Causes a Sulfite Allergy?

A sulfite allergy, like all allergies, is the result of an abnormal immune response to an otherwise harmless substance (known as an allergen).

Sulfites are chemical compounds found naturally in certain foods but are also manufactured for commercial use as food preservatives or flavor enhancers. They are even sulfites used in injectable medications as a preservative.

An allergy to sulfites can happen to anyone but is most common in people with asthma of whom 3% to 10% may be affected.

An increase in sulfite allergies led the U.S. Food and Drug Administration (FDA) to ban their use in fresh vegetables and fruits back in 1986. Today, food manufacturers must declare on product labels if their food contains more than 10 parts per million (ppm) of sulfites.

Food that contains over 100 PPM of sulfite include:

• Bottled lemon juice (non-frozen)
• Bottled lime juice (non-frozen)
• Dried fruits (except for dark raisins and prunes)
• Grape juices (white, white sparkling, pink sparkling, red sparkling)
• Molasses
• Pickled cocktail onions
• Sauerkraut and its juice
• Wine

Food that contains 50 to 99 PPM of sulfite include:

• Dried potatoes
• Fruit toppings
• Gravies/sauces
• Maraschino cherries
• Wine vinegar

Foods that contain 10 to 49 PPM of sulfite include:

• Avocado dip/guacamole
• Cheese (various)
• Ciders and cider vinegar
• Clams (canned or jarred)
• Clam chowder
• Cordials (alcoholic)
• Corn syrup
• Cornbread/muffin mix
• Cornstarch
• Dehydrated vegetables
• Fresh mushrooms
• Hominy
• Imported fruit juices and soft drinks
• Imported jams and jellies
• Imported sausages and meats
• Maple syrup
• Pectin
• Pickled peppers
• Pickles/relish
• Potatoes (frozen)
• Shrimp (fresh)

Injectable medications that contain sulfite include:

• Amikin (amikacin)
• Aramine (metaraminol)
• Celestone (betamethasone)
• Compazine (prochlorperazine) 
• Decadron (dexamethasone)
• Demerol (meperidine)
• Epinephrine (adrenaline)
• Garamycin (gentamycin)
• Isuprel (isoproterenol)
• Levophed (norepinephrine)
• Nebcin (tobramycin)
• Novocaine (procaine)
• Phenergan (promethazine) 

Sulfite Allergy Symptoms

A true sulfite allergy involves a specific immune reaction characterized by the release of an antibody called immunoglobulin E (IgE). The release of IgE sets into motion of chain of events in which the body is flooded with histamine and other inflammatory chemicals, triggering allergy symptoms.

With a sulfite allergy, the symptoms mainly involve the respiratory tract, causing asthma-like symptoms such as:

• Wheezing
• Chest tightness
• Coughing
• Shortness of breath
• Runny or stuffy nose
• Chest tightness

With that said, not all sulfite reactions are "true" allergies. More often, a person will experience a sulfite sensitivity in which the body cannot tolerate sulfites. Rather than releasing IgE, the immune system will respond by releasing a different antibody known as immunoglobulin G (IgG).

Food sensitivities like these are largely indistinguishable from a "true" food allergy.

The only exception is severe IgE reactions that can lead to anaphylaxis. This potentially deadly allergy is characterized by a steep drop in blood pressure and whole-body symptoms like:

• Sudden, severe rash or hives
  
• Rapid and weak pulse
• Difficulty swallowing
• Difficulty breathing
• Severe abdominal pain
• Nausea and vomiting
• Severe diarrhea
• Lightheadedness or fainting
• Swelling of the mouth, throat, or neck
• A feeling of impending doom

With sulfite sensitivity, elevations of IgG may make you ill, but it will not cause anaphylaxis.

How Is Sulfite Allergy Diagnosed?

Sulfite allergy rarely shows up in allergy skin tests. Even an IgE blood test commonly used to diagnose allergies may be unhelpful as a person is more likely to experience sulfite sensitivity (characterized by high IgG) than a true sulfite allergy.

If a sulfite allergy is suspected, your allergist will most likely perform an oral challenge. This involves drinking fluids with increasing amounts of sulfites as your lung function, heart rate, and blood pressure are monitored. A significant drop in lung function confirms the diagnosis.

Oral challenges should only be performed under medical supervision so that emergency treatment can be prescribed if anaphylaxis occurs.

Treatment Options

If you are diagnosed with a sulfite allergy or sensitivity, the best treatment is to avoid foods and medications that contain sulfites. Reading product labels can help you steer clear of them.

If accidental exposure occurs, the treatment can vary based on how sensitive you are to sulfites. Some of the more common include:

• Antihistamines: These drugs, available over-the-counter and by prescription, block the effects of histamine. Examples include Allegra (fexofenadine), Claritin (loratadine), and Zyrtec (cetirizine).
• Rescue inhalers: These medications, also known as bronchodilators, contain an inhaled drug called albuterol that opens airways and relieves asthma symptoms.
• Corticosteroids: These drugs, also known as steroids, quickly reduce inflammation in people with severe allergic reactions. A short course of prednisone is most commonly used.
• Sodium cromolyn: These oral drugs, delivered in capsule form, can also be useful in easing severe asthma symptoms caused by exposure to sulfites.
• Epinephrine (adrenaline): This synthetic hormone, self-administered with an EpiPen, is prescribed to people at high risk of anaphylaxis to quickly reverse symptoms if a reaction occurs.

Summary

Some people are allergic or sensitive to sulfites found in certain foods and medications. This can cause asthma-like symptoms and, on rare occasions, a potentially life-threatening allergy known as anaphylaxis.

If you are sensitive to sulfites, the most important thing to do is avoid foods and medications containing them. U.S. law requires food manufacturers to declare if sulfites are in their products.

If accidentally exposed to sulfites, treatment may include antihistamines, steroids, rescue inhalers, or epinephrine to relieve symptoms and avoid serious complications.