Allergic rhinitis (AR) is the most common immunological disorder and is characterized by an immunoglobulin E (IgE)-mediated inflammation induced by the allergen exposure. This review will consider some issues concerning pathophysiological aspects of AR: impact on asthma, response to decongestion, link with infections, response to specific immunotherapy, relationship with adiposity, effects on quality of life (QoL) and allergic inflammation. AR, even though not a serious illness, may be a clinically relevant disorder as it may present numerous complications and affect QoL, as reported in this review. Therefore, the management of AR patients should be rigorously careful and multi-disciplinary.