Sulfur dioxide via inhalation was detected in lymphocytes from 42 workers at an Indian fertilizer plant who were exposed to an average concentration of 41.7 mg/m3 (15.92 ppm) of sulfur dioxide (Yadav and Kaushik 1996).
Generally, sulfite sensitivity is detected in asthma patient who are steroid dependent. Sulfite sensitivity has also been linked to allergy. It is generally not found in persons who are both non-allergic and non-asthmatic. Even in patients who are sensitive to inhaled sulfites, the ingestion of foods containing sulfite (like beer and wine) may not cause a reactions, since the reaction depends on a number of factors.
There is no clear understanding of the mechanism by which inhaled sulfites trigger bronchospasm. It may be due to the formation of sulphur dioxide within the airways that affects the airway mucosa, and to some extent activates both the allergic antibody (IgE) underlying release of histamine.
Some asthma medications contain sulfites. Sulfite can trigger bronchospasm in a dose-related manner. For instance, both isoproterenol and isoetharine contain sulfite in sufficient dosage to trigger bronchospasm in most patients with asthma. They can also give rise to bronchospasm in those with asthma who are not sulfite sensitive.
Most importantly, molybdenum deficiency which we find in a majority of our patients. Molybdenum is the trace element contained in the enzyme sulfite oxidase which detoxifies sulfite to the inert and harmless sulfate (Pfeiffer, 1983; Sohler, 1983). Molybdenum is contained in legumes such as soybeans, navy beans and lentils that some people in developed countries avoid. In addition to molybdenum, some pantothenic acid, found to have a significant protective action against sulfur dioxide poisoning (Hoetzel, 1961) would also be useful.
Common symptoms which have been reported as commonly experienced by sulfite-sensitve individuals include wheezing, labored breathing, chest-tightness, cough, faintness, extreme shortness of breath, respiratory arrest, loss of consciousness, blue discoloration of skin, flushing, angioedema, hives, laryngeal edema, hypotension, generalized itching, contact dermatitis, episodic swelling of hands, feet and eye areas, mood changes, clammy skin, abdominal cramps, nausea, diarrhea and anaphylactic shock.
Anaphylax was detected resulting collapse of circulatory system and throat swelling, then death would occur. In the United States, including six death cases. While in Canada, 10 sulphite-related adverse reactions and one death, thought to be sulphite related (Yang and Purchase, 1985).