Oral allergy syndrome
Oral allergy syndrome (pollen-food allergy syndrome) is localized mouth and throat itching after eating raw fruits or vegetables in pollen-sensitized patients, caused by IgE cross-reactivity between labile pollen and plant-food proteins. Symptoms are usually mild and confined to the oropharynx, cooking abolishes them, and management is avoidance of the trigger raw food with epinephrine reserved for the rare systemic reaction.
- Topic reviewThe full article, organized the way the exam asks it.
- ABIM-format MCQsVignettes with an explanation for every wrong answer.
- Key factsThe numbers and thresholds worth memorizing, up front.
- AI tutorMedBrain answers the question you're stuck on.
What this article covers
- Overview
Definition: oral allergy syndrome (pollen-food allergy syndrome) is IgE-mediated oropharyngeal itching after eating certain raw fruits, vegetables, or nuts in patients sensitized to cross-reacting pollens.
- Epidemiology
Common in pollen-allergic patients: particularly adults with allergic rhinitis to birch or other pollens.
- Risk factors
Pollen sensitization / allergic rhinitis: the prerequisite, especially birch, ragweed, grass, or mugwort pollen.
- Pathophysiology
Cross-reactive IgE: IgE raised against pollen proteins (for example the birch major allergen Bet v 1 and profilins) cross-reacts with homologous proteins in plant foods.
- Clinical features
Oropharyngeal symptoms: immediate itching and tingling of the lips, tongue, palate, and throat.
- Differential diagnosis
Systemic IgE-mediated food allergy: reactions beyond the mouth (urticaria, wheeze, hypotension) and to cooked food, unlike oral allergy syndrome, which spares systemic sites and resolves with cooking.
- Diagnosis
Diagnose clinically from the pollen-food pattern, supported by targeted sensitization testing: the diagnostic basis is a history of immediate oropharyngeal itching after specific raw plant foods in a…
- Management
First-line, avoid the trigger raw foods and eat them cooked or peeled, which usually abolishes symptoms.
- Complications
Systemic reaction or anaphylaxis: uncommon (about 1 to 2 percent) but possible, more likely with certain foods or lipid transfer protein sensitization.
- Prognosis
Generally benign: most patients have persistent but mild oral symptoms controlled by avoiding raw triggers.
- Prevention
Eat culprit foods cooked, peeled, or processed rather than raw to prevent symptoms.
Read the whole article
Subscribing to Internal Medicine opens every article, the full question bank and MedBrain, on the web, iPhone and Android.
Related articles
- Allergic rhinitis
Allergic rhinitis is an IgE-mediated inflammation of the nasal mucosa causing sneezing, rhinorrhea, congestion, and itch on allergen exposure, classified as seasonal or perennial. Diagnosis is clinical, supported by skin or specific IgE testing to identify allergens, and treatment is allergen avoidance with intranasal corticosteroids first-line, escalating to combination therapy and allergen immunotherapy.
- Food allergy
Food allergy is an adverse immune response to a food, most importantly IgE-mediated reactions causing urticaria, angioedema, and anaphylaxis within minutes to two hours of ingestion. Diagnosis pairs a convincing history with skin or specific IgE testing and, when needed, a supervised oral food challenge, and management is strict allergen avoidance with epinephrine for reactions plus emerging oral immunotherapy.
- Anaphylaxis
Anaphylaxis is an acute, potentially fatal systemic hypersensitivity reaction from massive mast cell and basophil mediator release, presenting within minutes as skin, respiratory, cardiovascular, and gastrointestinal involvement after allergen exposure. It is a clinical, treat-first diagnosis, and intramuscular epinephrine is the immediate life-saving therapy.