The Role of Food Allergy in Rhinitis and Nasal Polyposis

Many patients feel that their rhinitis is triggered by foods. Although patients with rhinitis are frequently sensitised to foods, there is little evidence to support the role of food allergy in causing rhinitis in isolation. The presence of food allergy in infants may be a marker for subsequent development of allergic rhinitis. While many patients associate the ingestion of cow’s milk with an increase in the production and thickness of nasal secretions, milk and dairy product intake has not been found to be associated with an increase in symptomatic congestion or an increase in nasal secretions. Respiratory symptoms alone, as a manifestation of cow’s milk allergy, are rare. Food additive intolerance may manifest as chronic rhinitis. Tartrazine sensitivity may be present in aspirin-sensitive patients due to the similarity in the molecular structure of tartrazine to aspirin. The prevalence of sensitisation to foods is higher in patients with chronic sinusitis with nasal polyps than controls but there are no reported studies on the efficacy or effects of dietary restrictions on chronic rhinosinusitis. FOOD ALLERGY F allergy is an immune-mediated non-toxic reaction to food, which may be IgE-mediated or non IgEmediated.1 Oral ingestion is the primary route of exposure to food allergens, but the symptoms may rarely occur from direct inhalation of aerosolised particles containing allergenic food. Sixteen percent of patients in an Australian cohort of children with seafood allergy experienced rhinorrhoea and nasal pruritus on exposure to seafood vapours.2 EPIDEMIOLOGY OF FOOD ALLERGY Both the prevalence and spectrum of food allergens differ considerably between geographical regions.2 Food allergy is most prevalent in the first two years of life, with the prevalence at one year of age estimated at 6-8 percent, falling to about 1-2 percent in late childhood and remaining stable thereafter through to adulthood.3 The point prevalence of self-reported food allergy is approximately six times higher than that of challenge-proven food allergy.4 The most common food allergies in young children are cow’s milk (2.5%), hen’s egg (1.3%), peanut (0.8%), wheat (0.4%), soya (0.4%), tree nuts (0.2%), fish (0.1%), and shellfish (0.1%).3 Half of the infants who have an IgEmediated cow’s milk allergy develop sensitivity to other foods. Allergies to milk, soy, eggs, and wheat are likely to resolve in adulthood but other food allergies are more likely to persist. Adults are frequently allergic to shellfish (2%), peanuts (0.6%), tree nuts (0.5%), and fish (0.4%). It is difficult to identify the true prevalence of food-induced allergic rhinitis, because it frequently occurs in association with other food allergy symptoms such as asthma, eczema, oral allergic manifestations, urticaria, and gastrointestinal symptoms.