The present invention provides compositions comprising one or more RNAi agents (e.g., siRNAs, shRNAs, or RNAi vectors) for the treatment of conditions and diseases mediated by (e.g., featuring IgE-mediated hypersensitivity), as well as systems for identifying RNAi agents effective for this purpose. The compositions are suitable for the treatment of allergic rhinitis and/or asthma. In certain embodiments of the invention the RNAi agent is targeted to a transcript that encodes a protein selected from the group consisisting of the FC.epsilon.RI.alpha. chain, the FC.epsilon.RI.beta. chain, c-Kit, Lyn, Syk, ICOS, OX40L, CD40, CD80, CD86, Re1A, Re1B, 4-1BB ligand, TLR1, TLR2, TLR3, TLR4, TLR5, TLR6, TLR7, TLR8, TLR9, CD83, SLAM, common .gamma. chain, and COX-2. In addition, the invention provides RNAi agent/delivery agent compositions and methods of use. In certain embodiments of the invention compositions comprising an RNAi agent are delivered by the respiratory route.