Hospital de Dona Estefânia, Immunoallergy, Lisbon, Portugal
XXXII Reunião anual da EAACI. Milão, Junho de 2013.
Background: Food allergy occurs in 6 to 8% of the children and 3 to 4% of the adults. Allergic reactions to peanuts are particularly severe, with frequent anaphylactic reactions. Peanut allergy usually begins in childhood and often persists throughout life. The aim of our study was to evaluate the peanut sensitization/allergy evolution for a 6-year period in a group of patients previously studied.
Methods: A study was conducted in order to find the prevalence of peanut sensitization and allergy in a population followed in the Immunoallergology Department of Dona Estefânia Hospital. Skin prick tests (SPT) and a questionnaire about the ingestion of peanut were carried out in 2006 and 2012 to evaluate the peanut sensitization/ allergy. We included all of the 1415 patients who performed SPT to aeroallergens during the year of 2006 in our department. We reassess in 2012 the sensitized patients.
Results: In 2006, the prevalence of sensitization found was 2,8% (40 patients with positive peanut SPT), of whom 5 had symptoms with peanut ingestion, matching an allergy prevalence of 0,4%. Of the 40 patients, 19 were re-evaluated in 2012 (3 allergic and 16 with asymptomatic sensitization in 2006). The 3 patients allergic kept peanut eviction with no reported accidental ingestion or symptoms since 2006. The SPT remained positive. Of the 16 patients with asymptomatic sensitization, 12 maintained positive peanut SPT and 4 had negative peanut SPT. Of these 12 patients with SPT positive (asymptomatic in 2006), two reported symptoms after peanut ingestion (eczema and angioedema/tightness of the oropharynx), corresponding to new allergies. Two patients, who in 2006 had positive SPT but ate peanuts without reacting, did peanut avoidance on their own initiative.
Discussion: The small sample size is a limitation of this study, but some patients with asymptomatic sensitization to peanuts seem to develop symptoms in the future. It is important to understand if there are differences in the sensitization profile of these groups in order to predict the evolution. Similarly, it is important to consider which indication should we give to sensitized patients without symptoms - avoidance for all, because of the risk of developing symptoms, or only in certain cases?
Keywords: peanut, sensitization, allergy, skin prick tests