Bisulfite Sensitivity: The Asthma Trigger in Wine, Dried Fruit, and Shrimp
Bisulfite sensitivity affects an estimated 3-10% of adult asthmatics and up to 20% of steroid-dependent asthmatic children. It is NOT IgE-mediated allergy — the mechanism is disputed but involves sulfur dioxide inhalation from gastric acid, parasympathetic reflex bronchospasm, or sulfite oxidase deficiency. Sodium metabisulfite was named ACDS Allergen of the Year 2024. Found in wine, dried fruits, shrimp, and processed potatoes, bisulfites require oral provocation testing for confirmed diagnosis. Avoidance and asthma management are the cornerstones of care.
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Key facts
Bisulfite sensitivity affects an estimated 3 to 10 percent of adult asthmatics and up to 20 percent of steroid-dependent asthmatic children.
Sodium metabisulfite was named the American Contact Dermatitis Society Allergen of the Year for 2024, reflecting growing clinical recognition of this preservative as both a contact sensitizer and asthma trigger.
Bisulfite-induced asthma is NOT IgE-mediated — the 3 principal mechanisms are inhaled SO₂ from gastric acid, parasympathetic reflex bronchospasm, and sulfite oxidase enzyme deficiency.
The FDA banned sulfites from fresh raw produce in restaurant salad bars in 1986 following documented severe asthma fatalities from sulfite exposure.
What Are Bisulfites and Why Do They Trigger Asthma?
Bisulfites are a family of sulfur-containing preservatives used in food, beverage, and pharmaceutical manufacturing to prevent oxidation, browning, and microbial growth.
The major forms in use are: sulfur dioxide (SO₂, E220), sodium sulfite (E221), sodium bisulfite (E222), sodium metabisulfite (E223), potassium metabisulfite (E224), and potassium sulfite (E225). All interconvert in solution and ultimately release SO₂ — the active antimicrobial and antioxidant agent.
Sodium metabisulfite was named the American Contact Dermatitis Society (ACDS) Allergen of the Year in 2024, reflecting increasing clinical recognition of bisulfite sensitivity as a significant condition with both respiratory and skin manifestations. The NACDG added sodium metabisulfite to its 2017-2018 screening series, identifying a 2.7% positive rate — notable for a compound not previously in standard panels.
Critically, bisulfite sensitivity is NOT IgE-mediated allergy. This distinction matters enormously for diagnosis, management, and patient communication. Unlike pollen allergy or food allergy (IgE-mediated, involving mast cells and histamine), bisulfite-induced asthma operates through different mechanisms — and does not respond to anti-IgE therapy or standard allergen immunotherapy. Bisulfites are genuine asthma triggers, but they are not 'allergens' in the immunological sense. This page is distinct from the nitrites page (case-report true allergy, pharmacological headaches) and from the benzoates page (urticaria, aspirin sensitivity).
Symptoms of Bisulfite Sensitivity
Recognizing symptoms early helps you get the right treatment faster.
Acute bronchospasm
severeThe cardinal symptom of bisulfite sensitivity: wheezing, chest tightness, and difficulty breathing beginning within 5-30 minutes of consuming wine, dried fruits, shrimp, or other high-bisulfite foods. Responds to bronchodilator therapy.
Acute asthma exacerbation
severeIn asthmatics with bisulfite sensitivity, even moderate amounts of high-bisulfite foods can trigger a significant asthma attack requiring additional bronchodilator use or medical evaluation.
Coughing
moderateA persistent, often dry cough within minutes of bisulfite exposure, reflecting airway irritation and early bronchospasm, may precede or accompany wheezing.
Contact dermatitis (topical bisulfite)
mildBisulfites in topical products (eye drops, wound care solutions, some cosmetics, injectable medications) can cause contact dermatitis at the application site — the mechanism behind the NACDG 2.7% positive patch test rate.
Urticaria (hives)
moderateLess common than respiratory symptoms, hives can occur with bisulfite ingestion in sensitive individuals, though urticaria is less characteristic of bisulfite sensitivity than it is of benzoate sensitivity.
Rhinitis and nasal congestion
mildNasal symptoms including runny nose, sneezing, and congestion can accompany bisulfite-triggered asthma, reflecting the unified airway response to the same trigger.
Flushing and warmth
mildSome bisulfite-sensitive individuals experience facial flushing from SO₂-related vasomotor effects, distinct from the pharmacological flushing seen with nitrites.
Severe anaphylaxis-like reaction (rare)
severeVery rarely, bisulfite ingestion can trigger a severe multi-system reaction resembling anaphylaxis. Seek emergency care immediately for throat swelling, severe respiratory distress, or loss of consciousness.
When to see a doctor
The dominant manifestation of bisulfite sensitivity is respiratory — specifically, bronchospasm and asthma exacerbation following consumption of bisulfite-containing foods or beverages. The timing is characteristic: respiratory symptoms typically begin within 5-30 minutes of ingesting a bisulfite-containing food, with bronchospasm that may range from mild wheezing to severe acute asthma requiring emergency treatment. The classic scenario is an asthmatic who consistently experiences asthma symptoms after drinking wine, eating dried fruit, or consuming shrimp — and who improves with bronchodilator treatment, confirming the bronchospastic mechanism. Some patients notice the correlation themselves; others require a systematic evaluation to identify the dietary trigger. Beyond respiratory symptoms, bisulfites can cause contact and systemic allergic-type reactions: contact dermatitis from topical bisulfite-containing products (where the NACDG 2.7% positive rate is relevant) and occasional urticaria or angioedema — though this is less common than the respiratory presentation. The NACDG positive patch test rate reflects both true Type IV contact sensitization to bisulfites as a topical allergen and the known cross-reactivity with other sulfite forms. Seeking emergency care is essential if bisulfite ingestion causes severe bronchospasm, inability to speak in complete sentences, accessory muscle use during breathing, oxygen saturation below 95%, or any combination of respiratory distress with urticaria or hypotension.
Bisulfites as a Defined Asthma Trigger
The asthma connection is the central clinical story of bisulfite sensitivity — it is not a peripheral association but the primary manifestation. Sulfite sensitivity affecting 3-10% of the general asthmatic population represents a substantial clinical burden: in the US alone, with approximately 25 million asthmatic individuals, this translates to hundreds of thousands of people who may have dietary bisulfite triggers contributing to their asthma control. The non-IgE mechanism means standard allergy tests (skin prick test, specific IgE blood test) are negative for bisulfites in most cases — leading to missed diagnoses when patients and providers expect positive allergy tests to identify triggers. The NACDG 2017-2018 addition of sodium metabisulfite to the screening panel and the 2024 ACDS Allergen of the Year designation are increasing clinical recognition. For asthma management, bisulfite sensitivity should be considered in any asthmatic who has difficulty achieving control despite appropriate pharmacotherapy, especially if asthma flares have a dietary pattern. Pulmonary function testing before and after standardized bisulfite challenge (oral provocation with sodium metabisulfite, monitoring FEV₁) is the definitive diagnostic approach. Identifying and avoiding dietary bisulfite triggers is one of the few specifically modifiable factors that can reduce asthma exacerbation frequency.
Complications of Unrecognized Bisulfite Sensitivity
Unrecognized bisulfite sensitivity carries meaningful clinical consequences for affected asthmatics. The most serious complication is poorly controlled asthma: when bisulfite-triggered bronchospasm episodes are not identified as preventable, affected patients may have more frequent exacerbations, higher rescue bronchodilator use, increased emergency department visits, and higher healthcare costs than would be necessary with dietary bisulfite avoidance. Some patients receive progressive escalation of asthma pharmacotherapy — higher-dose inhaled corticosteroids, systemic corticosteroids, biological agents — without recognizing that dietary modification could reduce a significant portion of their exacerbation burden. Identifying bisulfite sensitivity can sometimes allow step-down of therapy when avoidance is implemented effectively. A separate complication is the paradoxical risk from bisulfite-preserved injectable epinephrine: some older formulations of epinephrine in multi-dose vials contain sodium bisulfite as an antioxidant preservative. A patient with bisulfite-sensitive asthma who receives epinephrine for another indication may theoretically have a paradoxical bronchospasm response to the bisulfite — though modern single-use epinephrine autoinjectors (EpiPen, Auvi-Q) do not contain bisulfites.
Poorly controlled asthma
Unrecognized bisulfite triggers contribute to exacerbation frequency and severity, potentially leading to unnecessary pharmacotherapy escalation when dietary avoidance could reduce the trigger burden.
Emergency department visits from food-triggered attacks
Acute asthma attacks following restaurant dining or wine consumption without bisulfite identification can lead to emergency care for preventable exacerbations.
Paradoxical response to bisulfite-preserved medications
Some injectable medications (older epinephrine formulations, some local anesthetics) contain bisulfites; a sensitized patient receiving these may experience worsening rather than improvement of respiratory symptoms.
Social and quality-of-life restrictions
Dietary avoidance of wine, dried fruits, restaurant seafood, and processed foods significantly affects social dining and food enjoyment for affected patients.
Missed diagnosis due to negative IgE tests
Because bisulfite sensitivity is non-IgE, standard allergy blood tests are negative — leading some patients and providers to incorrectly conclude that dietary triggers are not contributing to asthma.
Sources of Bisulfite Exposure
Bisulfites are among the most widely used food and beverage preservatives, and avoiding them entirely requires significant dietary vigilance. The highest-exposure food categories are:
How it works
The mechanism of bisulfite-induced asthma is non-IgE and remains incompletely understood — three principal pathways are debated. First, inhaled SO₂ pathway: when bisulfite-containing food contacts gastric acid, SO₂ gas is released and inhaled as a bolus, causing direct airway irritation and reflex bronchospasm — a sulfur dioxide-mediated irritant mechanism. Second, parasympathetic reflex bronchospasm: bisulfites may stimulate airway C-fibers and trigger cholinergic reflex bronchoconstriction, explaining why atropine can block bisulfite-induced responses in some patients. Third, sulfite oxidase deficiency: a rare enzyme deficiency results in inability to convert sulfite to sulfate, causing sulfite accumulation and airway sensitivity. None of these mechanisms involves IgE antibodies or mast cell degranulation — distinguishing bisulfite sensitivity categorically from IgE-mediated allergy.
Wine — particularly white wine, which uses higher SO₂ levels than red wine because it lacks the antioxidant tannins of red. A glass of white wine may contain 20-200 mg/L total SO₂. Red wine typically contains 50-150 mg/L. Many sulfite-sensitive asthmatics identify wine consumption as their most reliable trigger.
Dried fruits — including dried apricots, raisins, prunes, and dried figs preserved with SO₂. Brightly colored dried apricots are preserved with high SO₂; the darker, naturally dried versions have much less. A handful of SO₂-treated dried apricots can contain the same total sulfite as a glass of wine.
Shrimp and seafood — sulfites are used widely in shrimp processing to prevent melanosis (black spot) during storage and transport. Fresh-appearing shrimp in seafood markets may contain significant bisulfites from processing.
Processed potatoes — dehydrated potato products (instant mashed potatoes, frozen french fries, potato chips) often use sulfites to prevent browning. FDA banned sulfites from fresh raw potatoes in restaurant salad bars in 1986 following serious reactions, but processed potato products can still contain them.
Pharmaceuticals — bisulfites are used as antioxidant preservatives in injectable medications (epinephrine, some local anesthetics), nebulizer solutions, and eye drops. Patients who develop bronchospasm from an epinephrine injection may paradoxically be reacting to its bisulfite preservative.
Risk factors to watch for
Pre-existing asthma
Bisulfite sensitivity is essentially exclusive to asthmatics — particularly those with moderate-to-severe or steroid-dependent asthma. Bisulfites do not cause de novo asthma in non-asthmatic individuals under typical dietary exposures.
Steroid-dependent asthma
Up to 20% of steroid-dependent asthmatic children show bisulfite sensitivity, compared to 3-10% of adult asthmatics broadly — severe asthma is the highest-risk subgroup.
Aspirin/NSAID sensitivity
Some evidence suggests overlap between bisulfite sensitivity and aspirin-exacerbated respiratory disease (AERD/Samter's triad), though the pathways are distinct.
Occupational exposure to high SO₂ concentrations
Workers in food processing, wine production, and chemical synthesis with high bisulfite or SO₂ exposure have higher sensitization and respiratory sensitivity risks.
High dietary bisulfite intake from wine and dried fruits
Regular consumption of high-bisulfite foods (wine, dried fruits, shrimp) provides repeated exposure to SO₂ that may amplify airway responsiveness in susceptible asthmatics.
The Allergy Cascade
Exposure
Allergen contact
Detection
Immune recognition
IgE Response
Antibody production
Mast Cells
Histamine release
Symptoms
Allergic reaction
1.Exposure
Allergen contact
2.Detection
Immune recognition
3.IgE Response
Antibody production
4.Mast Cells
Histamine release
5.Symptoms
Allergic reaction
Diagnosing Bisulfite Sensitivity
Diagnosing bisulfite sensitivity requires clinical suspicion based on history — a pattern of asthma exacerbations consistent with dietary bisulfite triggers — followed by formal confirmation through oral provocation testing or patch testing depending on the clinical presentation. For respiratory bisulfite sensitivity: oral provocation testing with escalating doses of sodium metabisulfite, monitoring FEV₁ (forced expiratory volume in 1 second) before and after challenge, is the gold standard. This is typically performed in a pulmonology or allergy clinic with access to spirometry and emergency bronchodilator treatment. Standard IgE blood testing and skin prick testing are negative for bisulfites — a positive result would be incidental and does not confirm bisulfite-triggered asthma. For contact allergy (topical bisulfite products): patch testing with sodium metabisulfite is the appropriate test. The NACDG added sodium metabisulfite to its 2017-2018 screening series, finding a 2.7% positive rate. Patch testing at 1% or 2% aqueous concentration with 48-hour application and readings at 72-96 hours identifies true Type IV contact sensitization. FDA requires sulfite labeling on foods containing more than 10 ppm total SO₂ — a regulatory trigger that helps patients identify dietary sources. EU labeling requirements apply at >10 mg/L in beverages. Looking for E220-E224 on food labels helps identify bisulfite-containing products. For patients who want to identify co-existing IgE-mediated allergies that may be contributing to their asthma — dust mites, mold, pet dander, food proteins — at-home allergen testing through services such as Curex offers panels covering 40+ common allergens, with results in approximately 5 days. This testing identifies IgE-mediated triggers that could be treated with immunotherapy, while bisulfite sensitivity is evaluated through separate oral provocation testing with a pulmonologist or allergist.
Oral Provocation Testing (Gold Standard)
Escalating doses of sodium metabisulfite are administered orally under supervision, with FEV₁ monitoring before and after each dose. A confirmed positive requires a ≥20% fall in FEV₁ from baseline. Performed in a supervised clinical setting with emergency bronchodilator available.
Patch Test (Sodium Metabisulfite)
Sodium metabisulfite at 1-2% aqueous applied under occlusion for 48 hours with readings at 48 and 72-96 hours. Identifies contact sensitization. Part of NACDG supplemental series since 2017-2018; 2.7% positive rate.
Spirometry with Methacholine Challenge
Pulmonary function testing establishes asthma diagnosis and measures bronchial hyperresponsiveness. Methacholine challenge confirms airway hyperreactivity. Context for bisulfite provocation testing and establishes asthma severity.
Food and Symptom Diary
Detailed recording of all foods and beverages consumed alongside timing of asthma symptoms and peak flow measurements. Over 2-4 weeks, consistent patterns linking specific foods to symptom onset can identify suspected bisulfite triggers before formal provocation testing.
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The long-term solution to allergies
Instead of masking symptoms, immunotherapy retrains your immune system.
Standard allergen immunotherapy — both subcutaneous injections (SCIT) and sublingual drops (SLIT) — targets IgE-mediated allergic conditions. Bisulfite sensitivity is a non-IgE condition. Therefore, conventional allergen immunotherapy cannot directly treat bisulfite-triggered asthma. However, for many asthmatics with bisulfite sensitivity, IgE-mediated allergens also contribute to airway inflammation — house dust mites, mold, grass pollen, and pet dander are common co-triggers in atopic asthmatics. Treating these IgE-mediated allergic triggers through immunotherapy can reduce baseline airway inflammation and potentially decrease overall asthma reactivity, which may indirectly reduce the severity of bisulfite-triggered episodes by improving underlying asthma control. Sublingual immunotherapy from providers like Curex — custom-formulated drops taken at home for the specific allergens to which a patient is sensitized — can address the IgE-mediated component of mixed-trigger asthma. Plans start at $39/month and are covered by most insurance. This is an appropriate treatment for the IgE-mediated allergen component and may contribute to improved asthma control overall, but it does not address bisulfite sensitivity specifically. For patients with bisulfite-triggered asthma, the key clinical referrals are pulmonology (for spirometry, provocation testing, and pharmacotherapy optimization) and an allergist who can evaluate both bisulfite sensitivity and co-existing IgE-mediated triggers — then develop an integrated management plan.
Confirm bisulfite sensitivity via oral provocation testing
A pulmonologist or allergist administers escalating sodium metabisulfite doses while monitoring FEV₁ to confirm asthma trigger status.
Learn bisulfite label recognition
Identify E220-E224 designations, sulfite listings, and high-bisulfite food categories; develop practical avoidance strategies for home and restaurant dining.
Optimize asthma pharmacotherapy
Work with your pulmonologist to ensure ICS, rescue bronchodilator, and any add-on therapies are appropriate for your asthma severity and bisulfite sensitivity pattern.
Evaluate and treat co-existing IgE-mediated allergens
If IgE-mediated allergens also contribute to asthma, separate evaluation and immunotherapy (SLIT or SCIT) for those allergens reduces the total asthma burden.
“Evidence from controlled oral provocation studies confirms that bisulfite avoidance reduces asthma exacerbation frequency in confirmed bisulfite-sensitive patients. Many patients achieve substantial improvement in asthma control through a combination of dietary avoidance and optimized pharmacotherapy.”
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Living With Bisulfite-Sensitive Asthma
Living well with bisulfite-sensitive asthma is achievable with consistent dietary management and good baseline asthma control. The initial adjustment — learning which foods to avoid, how to navigate restaurant menus, and how to handle social situations involving wine — takes effort, but most patients internalize these skills quickly and find their asthma significantly more predictable. The social dimension of bisulfite avoidance deserves acknowledgment: wine is a central element of dining culture in many communities, and declining wine at dinners or asking detailed questions about food preparation in restaurants can feel awkward. Having a rehearsed, brief explanation ('I have asthma and sulfites are a trigger for me') tends to be well-understood and accepted. For patients who also have IgE-mediated environmental allergies contributing to their asthma (dust mites, mold, pet dander), the combination of dietary bisulfite avoidance and immunotherapy for the IgE-mediated triggers can produce synergistic improvement in asthma control — addressing both the dietary trigger and the underlying sensitization simultaneously.
The restaurant strategy
When dining out, ask your server specifically whether shrimp has been treated with sulfites, whether any dried fruits in dishes are sulfite-preserved, and what wines are available without added sulfites. Choosing grilled fresh fish, fresh poultry, and dishes prepared from whole fresh ingredients minimizes bisulfite exposure at restaurants.
Wine and bisulfite-sensitive asthma
White wine generally contains more SO₂ than red wine; organic wines labeled 'no added sulfites' contain the least. If wine is important to you, keeping a trigger journal while trialing lower-sulfite wines under your allergist's guidance may identify tolerable options for social situations.
Building a bisulfite-safe kitchen
Stock your kitchen with bisulfite-safe staples: fresh meats, fresh seafood, dark unsulfured dried fruits, homemade or carefully label-checked condiments, and fresh potatoes. Cooking from whole ingredients rather than processed foods naturally limits bisulfite exposure.
Asthma action plan integration
Work with your pulmonologist to add bisulfite exposure explicitly to your written asthma action plan — what steps to take if you accidentally ingest a trigger, when to use rescue inhaler, and when to seek emergency care. Share this plan with family members and close contacts.
Seasonal Patterns
January - December
medium intensity
Prevention Tips
Learn E220-E224 labeling
The EU and international food labeling codes for bisulfites range from E220 (sulfur dioxide) to E224 (potassium metabisulfite); recognizing these codes on ingredient labels identifies all bisulfite forms.
Avoid the highest-bisulfite foods
Wine (especially white wine), sulfite-treated dried apricots, shrimp, instant mashed potatoes, and frozen french fries are the most common bisulfite-trigger foods for sensitive asthmatics.
Choose 'no added sulfites' wine if wine is desired
Wine labeled 'no added sulfites' or 'low sulfite' typically contains significantly less total SO₂, though naturally occurring trace sulfites from fermentation remain.
Always carry rescue bronchodilator
Bisulfite-sensitive asthmatics should have their rescue inhaler accessible at all times; pre-treating before restaurant dining or events with uncertain bisulfite exposure may reduce reaction severity.
Inform healthcare providers about bisulfite sensitivity
Alert all physicians, nurses, and pharmacists to bisulfite sensitivity so that injectable medications (epinephrine formulations, local anesthetics) are specifically reviewed for bisulfite preservatives.
Choose naturally dried fruits over sulfite-preserved versions
Darker, sun-dried apricots and naturally dried raisins contain far less SO₂ than brightly colored sulfite-preserved dried fruits; choose these for snacking and cooking.
Prognosis for Bisulfite-Sensitive Asthma
The prognosis for patients with bisulfite-sensitive asthma is good when the diagnosis is established and appropriate management is implemented. Bisulfite sensitivity itself does not resolve spontaneously — the airways remain reactive to bisulfite triggers on an ongoing basis — but the practical impact on quality of life is highly manageable through dietary avoidance and asthma pharmacotherapy. Many patients experience dramatic improvement in asthma control once bisulfite sensitivity is identified and dietary avoidance implemented: exacerbation frequency decreases, rescue inhaler use drops, and some patients are able to achieve lower pharmacotherapy doses with their physician's guidance. The improvement often produces a virtuous cycle — better asthma control reduces baseline airway hyperresponsiveness, which can reduce reactivity to other environmental triggers as well. The 2024 ACDS Allergen of the Year designation for sodium metabisulfite is increasing clinical awareness, leading to earlier diagnosis and management for a condition that was historically underdiagnosed due to the non-IgE mechanism and negative standard allergy tests.
Key takeaways
Bisulfite sensitivity is NOT IgE-mediated allergy — it is a non-immune asthma trigger operating through SO₂ inhalation, parasympathetic bronchospasm, or sulfite oxidase deficiency
Sodium metabisulfite was named ACDS Allergen of the Year 2024, reflecting increasing clinical recognition of bisulfite sensitivity
3-10% of adult asthmatics and up to 20% of steroid-dependent asthmatic children are bisulfite-sensitive
Oral provocation testing with FEV₁ monitoring is the diagnostic gold standard — standard IgE allergy tests are negative and do not rule out bisulfite sensitivity
Wine (especially white wine), sulfite-treated dried fruits, and processed shrimp are the most important dietary triggers to eliminate
Bisulfite sensitivity is distinct from nitrite sensitivity (pharmacological headaches) and benzoate sensitivity (urticaria/aspirin-sensitive asthma)
Dietary Bisulfites: High-Risk and Safer Alternatives
Managing bisulfite sensitivity is fundamentally a dietary challenge, and identifying the highest-risk foods — while maintaining nutritional balance — is the central task. Bisulfites are used across a wide range of food categories, but the risk is not uniform: some foods contain far more SO₂ than others. High-bisulfite categories include wine (50-200 mg/L, the most common trigger), sulfite-preserved dried fruits (especially bright orange dried apricots, which may contain 1000-3000 mg/kg), shrimp processed with sulfites (highly variable — fresh-appearing commercial shrimp often treated), dehydrated potatoes (instant mashed potatoes, some potato chips), some condiments (pickled foods, wine vinegar, grape juice), and pharmaceutical preparations. FDA requires labeling at >10 ppm and banned sulfites from raw fresh fruits and vegetables in 1986 after reports of serious asthma reactions at restaurant salad bars. EU requirements apply at >10 mg/L in beverages. These regulations provide labeling protection for packaged products, but fresh restaurant preparations may use sulfite-treated produce without declaration. Natural foods (fresh fruits, vegetables, fresh unprocessed meats, whole grains) are largely bisulfite-free and should form the foundation of the bisulfite-sensitive patient's diet.
Foods that help
Fresh, unprocessed meats and fish
No bisulfite preservation — fish and meat purchased fresh rather than from processed or marinated preparations avoids the most common bisulfite sources in protein foods
Fresh fruits and vegetables
After FDA banned sulfites from raw fresh produce in 1986, fresh fruits and vegetables are among the safest food categories for bisulfite-sensitive individuals
Naturally dried fruits (dark/unsulfured)
Naturally dried apricots, prunes, and raisins without sulfite treatment are darker in color and contain trace SO₂ only from natural fermentation; safe for most bisulfite-sensitive patients
Low-sulfite or no-added-sulfite wines
Wines produced without sulfite additions (organic certifications typically limit SO₂) contain significantly less total sulfite than conventional wines; some bisulfite-sensitive individuals tolerate them
Foods to limit
Conventional wine (especially white wine)
White wine typically contains 100-200 mg/L total SO₂ — one of the highest dietary bisulfite sources and the most common food trigger for bisulfite-sensitive asthmatics
Sulfite-treated dried fruits
Bright-colored commercially preserved dried apricots, golden raisins, and dried cranberries may contain 1000-3000 mg/kg SO₂; a significant acute asthma trigger
Commercial shrimp (unless confirmed bisulfite-free)
Sulfites are widely used in shrimp processing to prevent melanosis; commercial shrimp should be assumed to contain bisulfites unless explicitly labeled otherwise
Instant and dehydrated potato products
Instant mashed potatoes, dehydrated potato slices, and some frozen potato products use bisulfites to prevent browning
Some condiments and pickled foods
Pickled vegetables, wine vinegar, grape juice, and some commercial condiments may contain bisulfite preservatives
Restaurant salad bar items
Despite FDA's 1986 ban on sulfites at fresh produce salad bars, some restaurant preparations (guacamole, cut fruit displays) may still contain bisulfite-treated ingredients
Bisulfite sensitivity is frequently missed because clinicians look for IgE and find nothing. The key trigger is always the same: asthma worsening after wine, dried fruit, or restaurant seafood — none of which requires an immune response to histamine to explain.
Frequently Asked Questions
Bisulfite sensitivity is a non-IgE respiratory condition in which bisulfites (sulfur dioxide and related compounds) trigger bronchospasm and asthma in susceptible individuals — primarily asthmatics. It is not a true IgE-mediated allergy in the immunological sense: IgE antibodies are not involved, mast cells are not the primary effectors, and standard allergy tests (skin prick test, specific IgE blood test) are negative. The mechanism involves SO₂ inhalation from gastric acid, parasympathetic reflex bronchospasm, or sulfite oxidase enzyme deficiency. 'Sulfite allergy' is commonly used colloquially but is technically imprecise — 'bisulfite sensitivity' or 'sulfite-induced asthma' are more accurate terms.
Wine is one of the most common bisulfite-trigger foods for sensitive asthmatics because it contains high concentrations of sulfur dioxide used as a preservative. White wine typically contains 100-200 mg/L total SO₂; red wine 50-150 mg/L. When swallowed, the acid environment of the stomach releases SO₂ gas from sulfites, which is inhaled and causes direct airway irritation and reflex bronchospasm in susceptible individuals. The reaction typically begins within 5-30 minutes of drinking. White wine tends to trigger more severe reactions than red wine because it contains higher SO₂ levels. Low-sulfite wines labeled 'no added sulfites' may be better tolerated by some bisulfite-sensitive asthmatics.
The diagnostic gold standard for bisulfite-triggered asthma is oral provocation testing: escalating doses of sodium metabisulfite are administered under medical supervision while spirometry measures FEV₁ before and after each dose. A confirmed positive requires a ≥20% fall in FEV₁. This is performed by a pulmonologist or allergist with emergency bronchodilator treatment available. Importantly, standard allergy skin prick tests and IgE blood tests are negative for bisulfites — a negative allergy test does not rule out bisulfite sensitivity. The NACDG patch test for sodium metabisulfite (2.7% positive rate) identifies contact sensitization, which is distinct from respiratory sensitivity.
No. Bisulfites and nitrites are completely different chemical compounds with different mechanisms and reaction profiles. Bisulfites (E220-E224: sulfur dioxide, sodium sulfite, sodium bisulfite, sodium metabisulfite, potassium metabisulfite) are asthma triggers in susceptible asthmatics through a non-IgE mechanism — the respiratory story. Nitrites (E249-E250: potassium nitrite, sodium nitrite) are cured meat preservatives whose documented human effects are pharmacological headaches from vasodilation and rare methemoglobinemia — not asthma. True IgE allergy to nitrites is essentially confined to one case report. Bisulfites were ACDS 2024 Allergen of the Year; nitrites have not been named AOY and have no established allergy mechanism.
The highest-priority foods to avoid are: wine (especially white wine, which has the highest SO₂ content), sulfite-treated dried fruits (bright orange commercial dried apricots, golden raisins — choose dark unsulfured versions instead), commercial shrimp (widely treated with sulfites in processing), dehydrated potato products (instant mashed potatoes, some frozen fries), and some condiments and pickled foods. FDA requires labeling when foods contain more than 10 ppm sulfite — look for 'sulfites,' 'sulfur dioxide,' 'sodium bisulfite,' 'sodium metabisulfite,' 'potassium bisulfite,' or 'potassium metabisulfite' on ingredient lists. Fresh, unprocessed foods are generally bisulfite-free.
Severe bisulfite reactions can occasionally resemble anaphylaxis, involving not only bronchospasm but also urticaria, angioedema, and hypotension. These multi-system reactions are rare compared to the more typical isolated asthma exacerbation pattern. Because bisulfite sensitivity is not IgE-mediated, the mechanism differs from classic IgE-mediated anaphylaxis — but the clinical presentation can be indistinguishable in severity. Patients who have experienced severe multi-system reactions to bisulfite-containing foods should carry an epinephrine autoinjector and consult an allergist for formal evaluation and a written emergency action plan.
No. Standard allergen immunotherapy — allergy shots (SCIT) and sublingual drops (SLIT) — targets IgE-mediated allergy. Bisulfite sensitivity is non-IgE, so immunotherapy does not treat it. However, many asthmatics have co-existing IgE-mediated allergen triggers (dust mites, mold, pet dander) that also contribute to their asthma. Treating these IgE-mediated allergens through immunotherapy can improve overall asthma control and may reduce the severity of bisulfite-triggered episodes by lowering baseline airway inflammation. A comprehensive allergy and pulmonology evaluation can determine whether immunotherapy for co-existing IgE-mediated allergens is appropriate alongside bisulfite dietary management.
Yes, bisulfites are used as antioxidant preservatives in some injectable and topical medications, and patients with bisulfite-sensitive asthma can react to these. Historically significant examples include some formulations of injectable epinephrine (used to treat anaphylaxis), certain local anesthetics, nebulizer solutions, and eye drops. Modern single-dose epinephrine autoinjectors (EpiPen, Auvi-Q) do not contain bisulfites. When receiving injectable medications in clinical settings, patients with documented bisulfite sensitivity should inform their healthcare team so that bisulfite-free formulations can be selected where available. This is especially important for patients requiring emergency medications, where bisulfite sensitivity could paradoxically cause the medication to worsen symptoms.
Wines labeled 'organic' or 'made from organic grapes' have stricter limits on added sulfites than conventional wine — US organic certification prohibits added sulfites, and EU organic wine can contain no more than 100 mg/L total SO₂ (versus 150-200 mg/L for conventional white wine). However, even organic wines contain some naturally occurring sulfites from the fermentation process. Whether low-sulfite organic wine is tolerated by bisulfite-sensitive asthmatics depends on individual sensitivity thresholds. Some patients do tolerate low-sulfite wines; others react to even trace amounts. Keeping a symptom diary while cautiously trialing low-sulfite wine options under your allergist's guidance is the safest approach.
The American Contact Dermatitis Society named sodium metabisulfite its Allergen of the Year for 2024. This designation reflects increased clinical recognition of bisulfite sensitivity as a significant condition affecting asthmatics and individuals who develop contact dermatitis from topical bisulfite-containing products. The ACDS Allergen of the Year program aims to highlight clinically important but underrecognized allergens to educate dermatologists, allergists, and patients. Previous AOY designations include propylene glycol (2018), acetophenone azine in EVA (2021), aluminum (2022), and benzyl alcohol (2026). The sodium metabisulfite designation in 2024 is helping increase patch testing for bisulfites and improving clinical diagnosis rates.
Medical References
- [1]American Contact Dermatitis Society (ACDS). Allergen of the Year 2024: Sodium Metabisulfite. Dermatitis. 2024.
- [2]North American Contact Dermatitis Group (NACDG). Addition of sodium metabisulfite to screening series 2017-2018: 2.7% positive rate. Dermatitis. 2019.
- [3]Stevenson DD, Simon RA. Sensitivity to ingested metabisulfites in asthmatic subjects. Journal of Allergy and Clinical Immunology. 1981;68(1):26-32.
- [4]Simon RA. Sulfite sensitivity. Annals of Allergy. 1986;56(4):281-8. Review of mechanism and clinical management of sulfite-induced asthma.
- [5]US Food and Drug Administration. Sulfites — Generally Recognized as Safe (GRAS); labeling requirement >10 ppm; ban from raw fresh fruits and vegetables (1986). FDA Regulations.
- [6]European Food Safety Authority (EFSA). Re-evaluation of sulfur dioxide (E 220), sodium sulphite (E 221), sodium bisulphite (E 222), sodium metabisulphite (E 223), potassium metabisulphite (E 224). EFSA Journal. 2016.
- [7]Vally H, Misso NL. Adverse reactions to the sulphite additives. Gastroenterology and Hepatology from Bed to Bench. 2012;5(1):16-23.
This content is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. Content reviewed by board-certified allergists at Curex.
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