Letters

Allergy to peanut, nuts, and sesame seed in Australian children

BMJ 1996; 313 doi: https://doi.org/10.1136/bmj.313.7070.1477c (Published 07 December 1996) Cite this as: BMJ 1996;313:1477
  1. R Sporik,
  2. D Hill
  1. Senior research fellow Director Department of Allergy, Royal Children's Hospital, Melbourne, Victoria, Australia 3052

    EDITOR,—Pamela W Ewan's study of nut allergy and Hugh A Sampson's accompanying editorial focus on an important public health issue.1 2 We have reviewed our database of the results of allergen skin tests undertaken by the department of allergy, Royal Children's Hospital, Melbourne, Australia. This is the main paediatric tertiary referral service for the state of Victoria (population 4.4 million, including 943 000 children under the age of 14 years). The range of clinical problems consisted essentially of atopic eczema in infants and anaphylaxis to food in young and older children. During 1990–6 sensitisation (>/=3+, wheal diameter approximately 3 mm) to peanut was found in 1601 infants and children, and sensitisation to a tree nut (almond, brazil, cashew, hazelnut, or walnut) in 590; 491 were sensitised to both (fig 1). This represents a combined prevalence of sensitisation of at least 0.2%. Sensitisation occurred early: 920 children aged under 24 months were sensitised to peanut and 270 to a tree nut.

    Fig 1
    Fig 1

    Maximum recorded sensitisation score for each child tested, 1990–6 (n = 4078). Sensitisation to nut extracts (Hollister-Stier, USA) was scored by comparing diameter of skin wheal in reaction to extract with that of wheal in reaction to histamine 1 mg/ml (on average 3 mm): 1+ if less than half diameter of histamine wheal, 2+ if equal to half diameter, 3+ if equal to diameter, 4+ if equal to twice diameter, and 5+ if greater than twice diameter

    While skin sensitisation to allergens does not always correlate with clinical problems, we have found a strong association with increasing levels of sensitisation to specific foods.3 Open challenge of 75 children with peanut butter gave an immediate (within 30 minutes) reaction in 85% of those with a skin test result of >/=4+. Conversely, only 13% of children with minor (</=2+) evidence of sensitisation reacted on formal challenge.

    We have also seen an increase in infantile eczema and anaphylaxis to food associated with sensitisation to sesame seed (fig 1). The number of children sensitised to sesame seed (531) was higher than the number sensitised to any one tree nut. Altogether 294 children were sensitised to both sesame seed and a tree nut, while 448 were sensitised to both sesame seed and peanut. Sesame seed is becoming common in the diet of this community and is found in tahini (ground sesame seed), dips, vegetable burgers, and muesli bars.4 Sensitisation also occurred early, being found in 317 children (60%) aged under 24 months. This was illustrated by an 11 month old infant who developed facial oedema, generalised urticaria, and wheeze when given his first taste of tahini, which his mother had consumed during pregnancy and lactation.

    Our previous studies have shown that multiple sensitisation to food allergens is common, especially in infants and young children undergoing expansion of their diets.5 The public health issue is not only the need for mandatory food labelling but also the need for paediatricians, trained in allergy, to evaluate infants and children who have adverse reactions.

    References

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    View Abstract

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