Table 2 Types of non-allergic rhinitis and proposed mechanisms

Vasomotor Rhinitis

CNS stimulation leading to inhibition of the sympathetic nervous system response and enhancement of the parasympathetic response[33].

   Gustatory Rhinitis

Muscarinc receptor stimulation[45].

   Infectious Rhinitis

Typically viral or bacterial induced inflammation[20].

   Non-allergic rhinitis with eosinophilia syndrome (NARES)

Eosinophilia leading to direct nasal mucosal damage and decreased mucocilliary clearance[48–53].

Occupational Rhinitis:[54–58]

   Annoyance

Subjective without evidence of inflammation.

   Irritant

Substance P induced neutrophilic inflammation.

   Corrosive

Agent directly damages nasal mucosa.

   Allergic

IgE mediated.

Other Rhinitis Syndromes:[60–63]

   Hormonally induced Rhinitis

Increased circulating blood volume and possible hormonal influences (e.g. estrogen, progesterone) leading to vascular pooling and smooth muscle relaxation causing nasal congestion.

   Rhinitis Medicamentosa

Direct mucosal damage by alpha-adrenergic agent causing loss of ciliated cells and interstitial edema[64, 65].

Atrophic Rhinitis:[66–68]

   Primary Atrophic Rhinitis

Infectious i.e. Klebsiella ozaenae

   Secondary Atrophic Rhinitis

Identifiable causes: Chronic sinusitis, turbinate surgery and irradiation