Is all Rhinitis due to Allergy?

“Doc, my ‘sinuses’ are acting up,” — a common complaint encountered by General Practitioners. Often, what the patient actually refers to is allergic rhinitis, which is commonplace in Singapore.

CAUSES OF RHINITIS

Nasoendoscopy and other otorhinolaryngology-related services are available at Tan Tock Seng Hospital’s ENT Clinic (Clinic 1B). For appointments, GPs should call 6359 6500.

Besides allergies, other causes of rhinitis include:

  • Atrophic rhinitis
  • Rhinitis of pregnancy
  • Nasal polyps/tumour
  • Occupation rhinitis (e.g. wood dust)
  • Cerebral spinal fluid (CSF) rhinorrhoea
  • Structural abnormalities (e.g. deviated nasal septum)
  • Medication such as sildenafil, methyldopa, ACE inhibitors and beta-blockers, NSAIDS, antidepressant
  • Systemic disease (e.g. granulomatous disease like sarcoidosis, hypothyroidism, immuno-deficiencies)

NON-ALLERGIC RHINITIS

Non-allergic rhinitis is a diagnosis of exclusion. It is distinguished from allergic rhinitis by the following:

  • Onset at a later age
  • Perennial symptoms
  • Absence of nasal or ocular itch and excessive sneezing
  • Prominent symptom of nasal congestion and post nasal drip

Typical trigger factors include household cleaning products, changes in temperature, perfumes, tobacco smoke, car exhaust and alcoholic beverages.

Two common subtypes are:

  1. Gustatory rhinitis, a vagal mediated reflex, that caused clear rhinorrhoea during meals.
  2. Vasomotor rhinitis or idiopathic rhinitis characterised by intermittent symptoms of congestion and/or watery rhinorrhoea when exposed to non-specific irritants e.g. air pollution or temperature change especially cold, dry air.

How to know the cause of rhinitis?

A detailed history focusing on identifying the triggering factor is taken. A thorough workout is performed to establish the cause of rhinitis. An allergy test (e.g. a skin prick test or in vitro testing) is performed to identify the specific allergen. This guides allergen avoidance and immunotherapy. A nasoendoscopy is performed to exclude structural causes and tumour.

By Dr Lim Keng Hua, Consultant, Department of Otorhinolaryngology, Tan Tock Seng Hospital