Nonallergic rhinitis

From Ganfyd

Rhinitis can be caused by non-allergic mechanisms. Irritants, hormones and structural abnormalities of the nose can all lead to symptoms of rhinitis. There are several different types of nonallergic rhinitis.

Causes

• Infective rhinitis
• Psychological and Emotional factors
• Drugs
  • Decongestant over-use - rhinitis medicamentosa
  • Beta blockers, aspirin, oral contraceptive pill
• Pollution - Atmospheric pollution, fumes, dust, industrial detergents and cigarette smoke
• Atmospheric conditions - Humidity, temperature
• Hormonal - Rhinitis of pregnancy
• Alcohol
• Smoking
• Exercise
• Systemic diseases - Wegener's granulomatosis, sarcoid, Horner's syndrome
• Idiopathic - Vasomotor rhinitis

Pathophysiology

There are several different mechanisms, all of which contribute to nonallergic rhinitis. Dust, gases, chemicals and irritants all have a direct irritative effect both on nasal mucosa and on nasal sensory nerves. This causes a local reflex action, which results in secretion and vasodilation, and causes autonomic effects.^[1] The effects of pregnancy, menstruation and oral contraceptives are thought to arise due to the action of oestrogen, which inhibits acetylcholinesterase, leading to increased parasympathetic tone^[2]. Physical obstruction in the nose can also cause rhinitis, including conditions such as deviated nasal septum, nasal valve collapse nasal polyps, neoplasms and foreign bodies.

Specific types of nonallergic rhinitis

Atrophic rhinitis

Also known as ozena, this is an extremely unpleasant form of rhinitis.

Aetiology

• Mainly in women
• Onset usually in puberty
• More common in orientals. Very rare in blacks.
• More common in Eastern europe and India
• Often secondary to trauma or extensive surgery to the nose

Pathology

• Atrophy of the nasal mucosa and bony nasal skeleton
• Degeneration of glands and nerve fibres
• Resiratory epithelium undergoes squamous metaplasia
• Bacterial proteolsis produces thick, gluey secretions

Clinical assessment

• Foul nasal odor
• Epistaxis
• Anosmia (so patient cannot detect foul smell)
• Crusting
• Nasal obstruction
• Nose contains gluey green-yellow secretions
• Nasal cavity is found to be wide, and the turbinates very small

Treatment

• Clean the inside of the nose with frequent douching with saline
• Steam inhalations
• Manual cleaning of the inside of the nose
• Ostomic powders sniffed into nose, such as dextrose
• Limited role for surgery - operations are designed to narrow the nose

Vasomotor rhinitis

Aetiology

• Generally diagnosis of exclusion.

Pathology

• Autonomic imbalance - overactive parasympathetics cause secretion and vasodilation
• May also be a specific reflex of the nasal mucosa

Clinical assessment

• Watery rhinorrhoea
• No sneezing or pruritis
• Nasal mucosa is pale and livid, with swollen turbinates

Treatment

• Role for antihistamines, decongestants and steroids
• Surgery has a limited role. Correction of deformities such as deviated septums helps. Cautery or submucosal diathermy of the turbinates may prevent secretions. Turbinate reduction is also used.

Rhinitis medicamentosa

This is a drug induced rebound congestion, usually due to overuse of nasal decongestants.

• Decongestants may cause an ischaemic state due to vasoconstriction, which may lead to the metabolic accumulation of vasodilatory chemomediators
• Benzalkonian chloride is a presevative in many nasal sprays. This may act as an irritant.
• Mucosa looks red and angry
• Best treatement is to stop the causative agent, and replace with an appropriate nasal steroid

References