Purpose of review: Due to the overlap of symptoms and signs in the various types of rhinitis, arriving at a precise diagnosis can be difficult. A diagnosis of idiopathic rhinitis can only be used when all other causes have been excluded and this review tries to clarify whom this term should be applied to, and the reasons why.
Recent findings: The current literature on idiopathic rhinitis is sparse. Haematological and immunological tests can help to distinguish which individuals have a predisposition to allergic mediated disease, but these results should be interpreted with caution because of the prevalence of false-positives. It has recently been shown that some patients previously labelled as 'idiopathic' suffer from a highly localized form of IgE-mediated allergy known as 'entopy'. Patients with idiopathic rhinitis probably represent a disparate group who may be suffering from a range of immunological or neuroregulatory disease processes in which an inability to down-regulate inflammatory processes may be as important as the process that initiates it.
Summary: To arrive at a diagnosis of idiopathic rhinitis all other forms of rhinitis must be excluded. With further research and a better understanding of the pathological processes involved in rhinitis, we may need to use the term 'idiopathic' less frequently but be more assured of its correct usage.