Seasonal rhinoconjunctivitis or hay fever is a common atopic condition that is frequently seen in clinical practice. Grass pollen is the major cause of pollinosis in many parts of the world. Immunotherapy is the only treatment that may affect the natural course of allergic diseases, and it may also prevent the development of asthma in patients with allergic rhinitis. With conventional subcutaneous desensitization the duration of treatment is around 3-5 years and usually comprises around 30-100 allergen injections. As high allergen doses have to be injected, allergic side effects may occur and patients must stay under medical supervision for at least 1 hour. Transcutaneous immunization (TCI) is a needle -free technique that delivers antigens and adjuvants to potent epicutaneous immune cells. The aim of the new epicutaneous route of desensitization is to more specifically target the immune system by loading Langerhans cells with the allergen. Lower antigen doses can be applied, such that side effects are reduced.

Inclusion criteria: Written informed consent History of grass pollen allergic rhinitis for at least two years Male and female between 18 years to 65 years Positive skin-prick test to grass pollen Positive conjunctival provocation test

Exclusion criteria: Eczematous skin lesions on the upper arms Perennial rhinitis due to perennial allergies or anatomical reason (polyps, septal deviation) Symptoms of infectious disease with rhinitis in between the last week Surgical intervention in between the last 30 days Pregnancy or nursing History of HIV or AIDS History of mastocytosis (cutaneous or systemic) History of significant cardiovascular disease Uncontrolled Hypertension (blood pressure > 160 / 95) History of significant pulmonary, renal and/or hepatic disease History of significant hematological disorder Moderate or severe asthma History of malignancy Significant neurological or psychatric disease History of active autoimmune disease Antihistamines with longed half-lives in the last week Systemic or topical steroids for 5 days Depot corticosteroids for the last two months Active infectious disease Adipositas per magna

Contraindicated medications:

• immunosuppressive agents
• Betablockers
• ACE-inhibitors, AT 2 Antagonists
• tricyclic antidepressants
• daily use of Beta-agonists or steroid inhalers
• Participation in another clinical trial /study at the moment or within the last 60 days