Cannabis sativa is an annual herbaceous plant from the Cannabaceae family that has been cultivated and consumed by humans for thousands of years. Its main uses include fiber production, seeds for human and animal food, and psychoactive medications. Indeed, cannabis is the most commonly consumed illicit substance among adolescents and poses a major public health issue. Allergic risks associated with cannabis have already been documented.

At the same time, the consumption of hemp seeds is increasing due to the current agro-food context and the rise of vegan and vegetarian diets. This new food raises questions about its potential allergic risks, especially since the prevalence and severity of food allergies have been steadily increasing over the years. In this context, cases of anaphylaxis related to hemp seeds have already been reported. However, the potential allergic risk associated with hemp seeds remains largely unstudied to date.

Several reasons make research into hemp seed allergies relevant:

i) increased exposure to Cannabis sativa in its various forms, with the possibility of finding identical or similar proteins in the seeds; ii) changes in dietary habits, with the vegan trend encouraging the consumption of many seeds, including hemp seeds.

All study-specific examinations are performed during the enrollment visit, which takes place during a routine medical visit

Inclusion Criteria:

• Patients aged 2 years or older

• Belonging to one or more of the target populations:

  i) Individuals with known or suspected cannabis allergy: Allergy or suspected allergy to hemp seed (HS) defined by A suggestive clinical history of HS allergy and Positive skin prick test (SPT) to HS (≥ 6 mm with erythema exceeding the control papule) and/or Basophil activation test (BAT) confirming HS allergy diagnosis OR Allergy or suspected allergy to hemp flower (female or male) defined by a suggestive clinical history of hemp allergy and positive SPT to hemp flower (≥ 6 mm with erythema) and/or ImmunoCAP IgE to hemp > 0.35 KU/L ii) Individuals allergic to tree nuts (hazelnut or walnut): Allergy to walnut defined by a suggestive clinical history of IgE-mediated walnut allergy and positive SPT to walnut (≥ 8 mm) and IgE to Jug r 1, Jug r 2, or Jug r 3 > 1 KU/L and/or BAT confirming walnut allergy diagnosis OR Allergy to hazelnut defined by a suggestive clinical history of IgE-mediated hazelnut allergy and positive SPT to hazelnut (≥ 8 mm) and IgE to Cor a 9, Cor a 11, Cor a 14, or Cor a 8 > 1 KU/L and/or BAT confirming hazelnut allergy diagnosis iii) Individuals allergic to seeds (sesame, flax, pumpkin, sunflower): Allergy to sesame defined by a suggestive clinical history of IgE-mediated sesame allergy and positive SPT to sesame (≥ 6 mm) and/or IgE to sesame and/or molecular components (Ses i 1 to Ses i 7) > 0.35 KU/L and/or BAT confirming sesame allergy diagnosis OR Allergy to flaxseed defined by a suggestive clinical history of IgE-mediated flaxseed allergy and positive SPT to flaxseed (≥ 6 mm) and/or IgE to flaxseed > 0.35 KU/L and/or BAT confirming flaxseed allergy diagnosis OR Allergy to pumpkin seed defined by a suggestive clinical history of IgE-mediated pumpkin seed allergy and positive SPT to pumpkin seed (≥ 6 mm) and/or IgE to pumpkin seed > 0.35 KU/L and/or BAT confirming pumpkin seed allergy diagnosis OR Allergy to sunflower seed defined by a suggestive clinical history of IgE-mediated sunflower seed allergy and positive SPT to sunflower seed (≥ 6 mm) and/or IgE to sunflower seed > 0.35 KU/L and/or BAT confirming sunflower seed allergy diagnosis

• Patients referred to the Allergy Unit at Angers University Hospital (CHU d'Angers) for skin prick testing, either in outpatient consultation or during hospitalization

• Patients affiliated with or beneficiaries of a social security system

• Patient or legal representative having signed an informed consent form

Exclusion Criteria:

• Pregnant women or women in labor
• Individuals deprived of liberty by an administrative or judicial decision
• Individuals undergoing involuntary psychiatric care
• Adults under a legal protection measure
• Individuals unable to express their consent
• Poor understanding of the French language
• Patients whose skin reactivity prevents the interpretation of the tests

Data will be shared upon reasonable request. Only de-identified data will be shared. Any data collected during the study may be shared. The protocol will be shared initially. Other documents may be shared at a later date upon request (e.g., the CRF to allow a collaborator to select the data they wish to access). The recipients of the data will be researchers. The data will be available for any purpose deemed relevant by the study investigator, based on a protocol provided by the requester, after verification of the obtaining of regulatory approvals, including the favorable opinion of an ethics committee.