The ‘food allergic march’ implies that children typically present with egg or milk allergy or both and then go on to develop additional food allergies followed in adolescence/adulthood by the oral allergy syndrome. Different allergic conditions may exhibit different genetic traits. A child has a 6–7-fold increased chance in developing peanut allergy if he or she has a family member with peanut allergy. An increase in allergic diseases over the last two decades has been linked to the recognition of new risk factors and the description of protective factors associated with a more ‘traditional lifestyle. Food allergy is thought to be on the increase, possibly in keeping with the increase in other allergic diseases such as asthma and eczema, although there is some epidemiological evidence of a plateau. The determination of IgG antibodies to food has no or little predictive value for diagnosis and dietary management of patients with food-allergic diseases.