Non-allergic rhinitis can be defined as a condition causing profuse chronic watery rhinorrhoea which is not allergic in aetiology. It is a general term encompassing a number of conditions, which include:
- Vasomotor rhinitis.
- Occupational rhinitis.
- Hormonal rhinitis.
- Drug-induced rhinitis.
- Non-allergic rhinitis with eosinophilia syndrome (NARES).
Non-allergic rhinitis is a chronic condition of the nasal mucosa showing symptoms of nasal congestion and rhinorrhoea with no evidence of allergic sensitisation through skin prick tests and dosage of serum-specific IgE for environmental allergens.
Non-allergic rhinitis is a very common condition in adults. It is thought to affect around 7% of the adult population and its incidence is increasing.
Common symptoms of non-allergic and allergic rhinitis include rhinorrhoea, sneezing, itchy nose and nasal congestion. In both types, the symptoms can be intermittent or almost continuous. Either type can result in acute rhinosinusitis by causing blockage of intranasal passages. Both types may be associated with asthma.
- This features excessive vascular engorgement of the nasal mucosa and profuse, watery rhinorrhoea. The cause is unknown but it appears to be related to an imbalance in the regulation of the parasympathetic and sympathetic systems, with the parasympathetic system predominating.
- It can be triggered by chemical irritants, changes in weather, excess humidity or a very dry atmosphere, and stress.
- The nasal mucosa can vary in colour from bright red to purple. Symptoms are usually intermittent.
- The turgescent mucous membrane varies from bright red to purple. The condition is marked by periods of remission and exacerbation.
Symptoms occur only in the workplace. Common inhaled irritants which trigger the condition include metal salts, animal dander, latex, wood dust and chemicals. However, over 300 substances have been identified. Occupational asthma may be an associated condition and is most likely to occur in the first year after the rhinitis develops.
Rhinorrhoea and nasal congestion are the principal symptoms. The condition may be linked to increases in oestrogen levels. Such states can occur in pregnancy, menstruation and puberty, and with the use of oestrogen medication. In pregnancy the condition usually occurs in the second month and stops after delivery. Oestrogen is thought to act in several ways, including stimulating parasympathetic activity, increasing acetylcholine levels, inhibiting sympathetic neurons and increasing the levels of hyaluronic acid in the nasal mucosa.
Having an underactive thyroid gland (hypothyroidism) can be another hormonal cause. It is thought to be due to turbinate oedema resulting from the release of thyrotropic hormone release.
This is also known as rhinitis medicamentosa. Prolonged use of topical nasal decongestants may result in rebound congestion of the nasal mucosa. This congestion may encourage further use of the decongestant, which may exacerbate nasal obstruction.
Other drugs known to cause this include antihypertensives (eg, angiotensin-converting enzyme (ACE) inhibitors, methyldopa, beta-blockers), chlorpromazine, gabapentin, penicillamine, aspirin, non-steroidal anti-inflammatory drugs (NSAIDs), cocaine, exogenous oestrogens and oral contraceptives.
This occurs after eating, especially hot and spicy foods. Vagus nerve activity causes nasal vasodilation. This results in watery rhinorrhoea. Typically, this occurs two hours after ingestion. The elderly are particularly prone to this condition. Occasionally, specific dyes or food preservatives can cause the same reaction.
Non-allergic rhinitis with eosinophilia syndrome (NARES)
NARES is an eosinophilic inflammation of the nasal mucosa, without evidence of an allergy or other nasal pathologies. Presenting symptoms are rhinorrhoea, sneezing, nasal pruritus and hyposmia. It may be related to the 'aspirin triad' of aspirin-induced asthma, nasal polyposis and aspirin intolerance. Abnormal prostaglandin metabolism may be involved.
- The clear discharge of vasomotor rhinitis may differentiate it from the purulent discharge and crusting of infective rhinitis. No specific allergen can be identified in the history.
- Occupational rhinitis may be identified by a history of symptoms only occurring in the workplace. Provocation by nasal inhalation or skin testing may be needed to confirm the trigger irritant.
- Patients with NARES may have a higher than normal amount of eosinophils seen on a nasal smear.
Non-allergic rhinitis remains a poorly managed and often difficult-to-treat condition. In general, the most effective therapy is the combination of an intranasal antihistamine and an intranasal corticosteroid.
- Humidified air may be helpful.
- Topical antihistamines are the usual first-line medical treatment.
- Sympathomimetic amines (eg, pseudoephedrine) can be effective but topical formulations (eg, ephedrine nasal drops) are only licensed for use up to seven days. Prolonged use can lead to rebound congestion on withdrawal (see 'Rhinitis medicamentosa', below). Ephedrine and pseudoephedrine cause fewer problems than xylometazoline in this respect. Ephedrine are not licensed for use in children under the age of 12 years and xylometazoline is not licensed for use in children under the age of 6 years.
- Topical corticosteroids (eg, beclometasone) may be beneficial in some cases.
Avoidance of the trigger irritant is the ideal treatment but cannot always be achieved in reality. Nasal corticosteroids and second-generation antihistamines are the medical treatments of choice.
Management will depend on the underlying condition. Pregnant patients may present with vasomotor rhinitis and may benefit from nasal saline solution, exercise and topical pseudoephedrine. Hormonal contraceptives might protect young women from allergies including rhinitis.
Treatment depends upon removal of the offending medication. In terms of sympathomimetics, it takes 7-21 days for the condition to resolve. Patients may be resistant to withdrawal of the preparation, as symptoms are likely to increase as it is withdrawn but this may be mitigated by using a nasal corticosteroid during this period or by reducing medication gradually (eg, one nostril at a time).
Ipratropium bromide nasal spray is useful in this condition. The elderly may be troubled by its adverse effects of loss of bladder control. An oral antihistamine would be a second-line option.
Steroid nasal sprays are useful, as they appear to have a direct action on eosinophils, preventing the activation of the allergic cascade which leads to inflammation.
Non-allergic rhinitis can affect quality of life considerably. It is associated with interrupted sleep patterns, drowsiness in the daytime, irritability and poor concentration.
Further reading and references
Settipane RA, Kaliner MA; Chapter 14: Nonallergic rhinitis. Am J Rhinol Allergy. 2013 May-Jun27 Suppl 1:S48-51. doi: 10.2500/ajra.2013.27.3927.
Guidelines for the management of allergic and non-allergic rhinitis; British Society for Allergy and Clinical Immunology (January 2008)
Becker S, Rasp J, Eder K, et al; Non-allergic rhinitis with eosinophilia syndrome is not associated with local production of specific IgE in nasal mucosa. Eur Arch Otorhinolaryngol. 2016 Jun273(6):1469-75. doi: 10.1007/s00405-015-3769-4. Epub 2015 Sep 5.
Greiwe JC, Bernstein JA; Combination therapy in allergic rhinitis: What works and what does not work. Am J Rhinol Allergy. 2016 Nov 130(6):391-396. doi: 10.2500/ajra.2016.30.4391.
Greiwe J, Bernstein JA; Nonallergic Rhinitis: Diagnosis. Immunol Allergy Clin North Am. 2016 May36(2):289-303. doi: 10.1016/j.iac.2015.12.006. Epub 2016 Mar 12.
Lieberman PL, Smith P; Nonallergic Rhinitis: Treatment. Immunol Allergy Clin North Am. 2016 May36(2):305-19. doi: 10.1016/j.iac.2015.12.007. Epub 2016 Feb 26.
Wei J, Gerlich J, Genuneit J, et al; Hormonal factors and incident asthma and allergic rhinitis during puberty in girls. Ann Allergy Asthma Immunol. 2015 Jul115(1):21-27.e2. doi: 10.1016/j.anai.2015.04.019. Epub 2015 May 23.