Food allergy is an immune reaction, triggered by food protein allergens, of varying severity, from mild local reaction to life threatening anaphylaxis and fatalities.

Peanut is a plant from the botanical family of the Fabaceae, more commonly known as legumes. The prevalence of peanut and tree nut allergy is increasing. In France (ELFE cohort), it is estimated to 0.93%. The tree nuts include mainly almond, hazelnut, pistachio, cashew nut, walnut, pecan nut and Brazil nut. Allergy's prevalence is estimated to 0.54% in children up to 5.5 years. Peanut allergy is a main cause of anaphylaxis and deaths due to food allergy.

Recurrence of food allergy is a main concern. The risk has been estimated to 10% per year for peanut.

In France, Data in real-life on the rate of recurrence of allergic reactions and anaphylaxis to peanut/tree-nut as well as risk factors, are lacking.

The objective of this study is to assess the frequency of allergic reaction to peanut and tree-nuts, to describe the reactions' characteristics and risk factors.

Inclusion Criteria:

• Confirmed allergy to peanuts and/or nuts

Exclusion Criteria:

• Other chronic diseases, except allergic comorbidities (asthma, rhinitis, atopic dermatitis, other food allergy)

Patients followed in the Pediatric Allergy and Pulmonology Unit, CHU Lille, aged 0-18 years with peanut and/or tree nut allergy