The present study will investigate the long term effect of allergen immunotherapy in a real-life study in children with allergy undergoing subcutaneous or sublingual immunotherapy with grass pollen, birch, house dust mites or venom.

The study will include children aged 5- 18 years who are treated with immunotherapy at Hans Christian Andersen Children' Hospital, Odense University Hospital.

Informed consent to be registered in a database and to receive a questionnaire 5 and 10 years after end of treatment are obtained before start of immunotherapy.

Base line data include information from the patient record: symptoms, medication, blood test and skin prick test results. During treatment effect, medication use, lung function and adverse events are monitored systematically once a year.

The questionnaires 5 and 10 years after end of treatment will focus on allergy symptoms, use of medication and asthma symptoms.

Inclusion Criteria: treated with allergen immunotherapy at HCA Children'sHospital, Odense University Hospital -

Exclusion Criteria: received less than 12 months of treatment with allergen immunotherapy

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Children with moderate to severe allergy to grass pollen, birch, house dust mites or venom who are prescribed allergen immunotherapy