Rhinitis is one of the most prevalent immunological disorders, a global problem affecting between 10% and 25% of individuals in different countries, increasing constantly. Historically, rhinitis has been described as a disease of no importance "except to those who suffer from it". In fact, the symptoms have a marked effect upon quality of life similar to that experienced by sufferers with mild to moderate asthma and chronic back pain. It's economic impact is also therefore significant due to reduced productivity in the workplace. This guide gives professionals the information to make as precise a diagnosis as possible, in order for successful treatment.