Prevalence of sensitivity to sulfiting agents in asthmatic patients

Attenuation of the metabisulfite-induced bronchoconstrictive response by pretreatment with cromolyn

In a retrospective analysis of 1,544 patients who underwent provocative challenge with metabisulfite at the National Jewish Center between 1983 and 1987, an abnormal airway response to metabisulfite was found in 52 patients, an incidence of 3.4 percent. There was no relationship between this abnormal airway responsiveness to metabisulfite and the degree of airway obstruction present, or the degree of airway reactivity as assessed by the response to inhaled bronchodilator or exercise testing. In a pilot study, we found that the administration of cromolyn sodium prior to metabisulfite challenge markedly attenuated the abnormal bronchoconstrictive response in nine of ten patients. We conclude that a metabisulfite-induced bronchoconstrictive response cannot be predicted on the basis of the degree of airway obstruction or airway reactivity and that pretreatment with cromolyn sodium may attenuate the abnormal response.

Sulfite-treated lettuce challenges in sulfite-sensitive subjects with asthma

This study was designed to determine whether lettuce treated with a commercially available sulfite-containing freshener prepared according to manufacturer's directions could provoke reactions in sulfite-sensitive subjects with asthma (SSAs). Five adult SSAs with stable asthma who had multiple prior reactions to double-blind, placebo-controlled, sulfite-capsule challenges were studied. Each patient ingested, in a double-blind, placebo-controlled fashion, four portions of lettuce (3 oz) pretreated with one of two commercially available, nearly identical vegetable fresheners. One freshener contained sodium bisulfite and was used on one portion of lettuce. The other freshener contained no sulfite and was used on three portions of lettuce. The fresheners were prepared and the lettuce was treated according to label instructions. After baseline spirometry, the SSAs consumed the lettuce samples with the same dressing of their choice, serial spirometry was performed, and a positive reaction was defined as a greater than 20% drop in FEV1 decreased 0% to 7%; mean, 3%. Two of the subjects experienced severe reactions to the sulfite-treated lettuce. One of these reactions was life threatening; the other reaction occurred despite placing only 30% of the usual sulfite dose on the lettuce. This study has demonstrated that sulfite-treated lettuce is capable of provoking bronchospasm in SSAs and suggests that such food is one cause of restaurant-provoked asthma in these individuals.

[Severe complications related to metabisulfites]

Metabisulfite intolerance is encountered in 8 p. 100 of cases of extrinsic asthma and in 20 p. 100 of cases of the "aspirin triad" with nasosinusal polyposis, asthma and aspirin sensitivity. The possibility that anaphylactoid shock or acute severe asthma leading to status asthmaticus, might be related to sulfite sensitivity must be well known. Two case reports are set out. The first observation is that of a 35-year-old woman suffering from intrinsic asthma with alcohol intolerance, who developed status asthmaticus a few minutes after intravenous administration of Doxycycline associated with a metabisulfite preservative. The other 33-year-old patient presented with an acute bronchospasm in the course of a fiberoscopy using Lidocaine associated by mishap with epinephrine, as local anesthetic. The authors point to the miscellaneous drugs containing sulfites, that are employed in asthmatics by different routes, i.e. parenteral, oral, inhalational and other local treatments. Heavy metabisulfite intake may also arise from daily alcohol consumption. Sulfite intolerance could contribute to the persistence of chronic inflammatory processes in bronchial asthma and therefore should be systematically investigated.