A 'big, affectionate kiss' from someone who has recently eaten peanuts or a peanut-containing product could trigger an allergy to the nut in some children.

This is an even greater risk in a baby who already has eczema, as infants with this condition are known to be at much higher risk of developing peanut allergy.

A sloppy kiss can transfer up to 12ml of saliva to a baby's forehead, with a single kiss delivering up to 88.8mg of peanut proteins to the recipient, according to new Australian research. This could be sufficient to induce sensitisation of that child to peanut allergen.

Kissing and cuddling of babies should obviously not be avoided entirely as they are essential for a child's social and emotional development, and most children who become sensitised do not develop an allergy. However, around one in seven sensitised children do, so avoiding high-saliva-content kisses after eating nut products is clearly a wise precaution.

Other possible routes of environmental peanut exposure include contaminated hands and surfaces in the home. Traces of the nut left on these after eating or preparing peanut-containing foods can persist, even after washing, and may be inadvertently transferred to a baby.

Peanut contamination can be acquired from a surprising range of seemingly safe foods, such as fruit yogurts, chilli con carne, margarine, packet soup, salad dressings, cakes, biscuits and ice cream.

First published in May 2007

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