COVER STORY
ADULT FOOD ALLERGY: POLLEN FOOD SYNDROME Kate Roberts RD Clinical Dietetic Advisor, Allergy UK
In primary care, it is common to see adults developing reactions to food. These foods can seem obscure and the symptoms can be vague. Dietitians are well placed to investigate these symptoms further, help identify trigger foods and educate on how people can manage their allergies. This article delves into Pollen Food Syndrome (PFS) which is increasing in the UK. Specialist adult allergy centres are not common and PFS sufferers are mainly seen in primary care or in general dietetic clinics. On average, 2% of the adult population across the UK suffer with PFS, but this ranges from 0.8% in Aberdeen to 4.1% in Croydon.1 It most commonly affects adults who have Allergic Rhinitis (hay fever); the reactions are caused due to the proteins in the food that are similar to those in pollen. The body mistakes them for allergens and this causes an allergic reaction. This is most common in birch pollen, as the main allergen Bet v 1 is highly cross-reactive to many plant foods.2 It is estimated that 50-90% of people who are sensitised to birch pollen also have PFS.1 The prevalence of Allergic Rhinitis has trebled within the last 30 years3 and, therefore, it is very likely that this is a condition that will be seen more in primary care and general dietetic practice. SYMPTOMS
The symptoms of PFS usually occur quickly (usually within five to 10 minutes) after eating and commonly involve itching, tingling or a burning sensation within the mouth, ears or throat. Swelling is less common but can occur in the lips, tongue and throat.2 More uncommon reactions include rashes, nausea, vomiting, sneezing and a blocked nose. More serious reactions 12
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could occur if large amounts of trigger foods are consumed and in very rare cases PFS can cause anaphylaxis. PFS is often referred to as Oral Allergy Syndrome (OAS), a term used to describe Mugwort any crossreactive plant food allergies. These include latex and non-specific lipid transfer proteins (LTPs); these allergies are not as common in the UK as PFS and result in more severe allergic reactions.1 Sensitisation to LTP allergens is more common in Mediterranean countries. If you have a patient of Mediterranean origin with severe reactions to fruit such as peaches, it is important to refer immediately to a specialist allergy team. FOODS ASSOCIATED WITH PFS
The foods that people react to depend on the pollen that they are sensitised to. Reactions only occur when the foods are raw or lightly cooked which can cause confusion in those having the reactions. Table 1 shows the main foods associated with allergic reactions and as pollens vary in different countries, the common UK pollens have been highlighted.