Allergen specific immunotherapy (ASIT) and environmental control are the only etiologic treatments of allergic rhino-conjunctivitis, asthma and atopic dermatitis. The clinical benefit of ASIT relies on the selection of the patients and the identification and administration of the allergen, or allergens. Different routes of administration have been investigated, including subcutaneous, intradermal, epicutaneous, sublingual, inhaled, or intra-lymphatic. While subcutaneous and sublingual allergen specific immunotherapy may require from 3 to 5 years of treatment, clinical efficacy with intra-lymphatic treatment can be achieved after 3 injections. The most severe side effect of ASIT is anaphylaxis. Novel approaches are being investigated to reduce the allergenicity of immunotherapy vaccines, maintaining immunogenicity. Peptide immunotherapy has been directed mostly against autoimmune diseases, but the use of synthetic peptides for ASIT is a promising field in basic science, applied immunology and in clinical development. Short synthetic peptides bear allergen-specific CD4 T-cell epitopes which induce tolerance by stimulating regulatory (Treg) and Th1 cells. In the present patent review, we describe new trends in allergen immunotherapy using peptides, which, from a clinical point of view, are promising.