Pathophysiology of nasal symptoms.

Symptoms are perceived by the patient and all nasal symptoms must eventually relate to stimulation of sensory nerves or some change in the activity of the CNS. Although it is the symptoms that are of prime importance to the patient, the role of sensory nerves and psychology in the generation and perception of symptoms has been relatively neglected compared to the large amount of research on inflammatory mediators. This paper discusses how physical and chemical changes in the nasal epithelium result in the generation of inflammatory mediators that are responsible for symptoms. Inflammatory mediators can cause symptoms in three ways. (1) By having direct action on glands and blood vessels to cause glandular secretion, vasodilation, increased vascular permeability, and transudation of a plasma exudate. (2) By stimulation of sensory nerve endings to cause reflex glandular secretion, sneezing, and sensations such as itching, irritation, pain, and pressure. (3) By effects on the central nervous system to cause, headache, fever, tiredness, and mood changes.