Diagnosing and managing peanut allergy in children.
The prevalence of peanut allergy is thought to be rising with 1 in 70 children affected in the UK. Accidental exposures are frequent and nut allergies are the leading cause of fatal food allergic reactions. Allergic reactions to peanuts are nearly always an immediate, type 1-mediated hypersensitivity response. The typical physiological response associated with such a reaction includes smooth muscle contraction, mucous secretion and vasodilatation. These responses are typically rapid in onset and can lead to systemic effects i.e. anaphylaxis. Peanut allergy most commonly presents in the first five years of life. More than 90% of nut allergic children will have a history of eczema, asthma, rhinitis or another food allergy. The clinical diagnosis of peanut allergy is made from a typical history in combination with clinical evidence of sensitisation i.e. the presence of peanut-specific IgE or positive skin prick tests. There are several predictors of future severe reactions, including: poorly controlled asthma, multiple allergies and previous severe reactions. The amount of peanut consumed is likely to be the major determinant of severity. Management includes a comprehensive package of allergen avoidance advice, provision of emergency medication, family and school/nursery training. The mainstay of management is advice on allergen avoidance. Verbal and written advice should be given. Fast-acting antihistamines as well as adrenaline autoinjectors should be provided as appropriate. Undertreated asthma is a known risk factor for severe reactions and therefore patients with co-existent asthma should undergo regular review.