Clinical care of food allergy and food anaphylaxis in children

Abstract

The spectrum of food allergy recapitulates the different clinical presentations ranging from trivial oral itchiness, urticaria, angioedema, gastrointestinal symptoms to life-threatening asthma and cardiovascular shock often referred to as anaphylaxis. While the IgE mechanism is well comprehended now, however, the underlying pathogenesis for non-IgE mechanism is diverse and still elusive. The clinical management for food allergy and anaphylaxis is evolving from largely avoidance basis towards active intervention including early introduction of allergenic food in infant diet and oral tolerance induction. This thesis presents a combination of original epidemiological and clinical data as well as audit on service provision from the author's experience in Hong Kong and Melbourne to uncover new leads in the field.

Our study on disease prevalence highlighted food allergy is becoming a new public health concern in Hong Kong. At least 4-5% of children got clinical symptoms and likely 2-3% of children got seafood allergy and 0.3-0.5% of children may have peanut allergy. Both of them often give rise to severe symptoms and are usually persistent till adulthood. Our Melbourne peanut study shed lights on important clinical predictors for peanut allergy remission. The data on tree-nut co-sensitization pattern peanut allergic children is intriguing and development of new nuts sensitization and even multiple nuts sensitization while on strict avoidance is exceedingly common which casts serious doubt on adopting such approach. Our study on relationship of eczema severity and food allergy failed to reveal multiple food allergy nor any specific food allergy per se as a surrogate that may predict eczema severity. Instead general “atopyness” as reflected by total IgE level seems to play a larger role. Using cow’s milk and peanut allergy as two prototypes of food allergy, this thesis has detailed the current practice and future endower like the prospects of application of immunotherapy. The author has also spent good length in discussion about service gaps and challenges pertaining to local practice. Also the thesis offers the way forward to address such deficiencies by recommending improvement measures and service/training modeling.