The invention concerns bifunctional fusion molecules for the treatment of IgE-mediated allergic conditions and Fc.epsilon.RI-mediated autoimmune conditions. The invention provides a new therapeutic approach for the treatment of both acute and late-phase allergic responses due to ingestion, inhalation, cutaneous and parenteral exposure to allergens, responses including asthma, allergic rhinitis, atopic dermatitis, severe food allergies, chronic urticaria and angioedema, as well as anaphylactic reactions due to exposures such as bee stings or penicillin allergy. In addition, the invention provides for a novel, safer and more efficacious form of allergy vaccination.