Prevalence of food allergy in the world has been inscreasing in recent years. Among nut allergy, hazelnut allergy is the most widespread in Europe and particularly in France. The current treatment for hazelnut allergy is based on eviction and wearing of an emergency kit with adrenaline auto-injector pens, to be used in the event of severe anaphylactic reaction. Oral immunotherapy (OIT) is a treatment that is now increasingly being offered as an alternatice to eviction. There are few published data concerning hazelnut OIT in Europe, where its consumption is nevertheless very high.

The main objective of our study is to evaluate the clinical efficacy of the hazelnut OIT protocol, implemented since 2015 in the pneumology and allergology-paediatric department of the Mother and Child Hospital in Bron, in hazelnut allergic children under 18 years old.

The secondary objectives will be to evaluate the biological efficacy and clinical tolerance of the protocol.

The study is retrospective and observational, and is based on the collection of medical data from patient records.

Inclusion Criteria:

• Aged Under eighteen years old
• Hazelnut allergy (clinically and biologically)
• Under IOT hazelnut protocol in Pneumo/allergology-paediatric departement of the Mother and Child hospital in Bron

Exclusion Criteria:

• Lack of consent to be included in the study (by their parents)
• Age > 18 years old

Children aged under eighteen. With hazelnut allergy (convincing clinical history and positivity of hazelnut skin prick test history or specific IgE) Under IOT hazelnut protocol in Pneumology/allergology-paediatric department of the Mother and Child Hospital in Bron