Allergic Rhinitis,Vasomotor Rhinitis and Nasal Polyps

Hypersensitivity of the nasal and sinus mucosa may be allergic or nonaller- gic in aetiology. Allergic rhinitis is mediated by reaginic antibody (IgE). Non- allergic vasomotor rhinitis does not involve the type I allergic response. It may be subdivided into the eosinophilic type, in which there are abundant eosinophils in the nasal secretion, and the non-eosinophilic type, which is probably secondary to autonomic dysfunction.

ALLERGIC RHINITIS

Following exposure to a particular allergen, the susceptible individual pro- duces reaginic antibody (IgE), which becomes bound to the surface of a mast cell. Such cells abound in nasal mucosa and when fixed to IgE molecules are said to be sensitized. Further exposure to the specific aller- gen causes its binding to the IgE of the sensitized mast cell, degranulation of the cell and release of histamine, slow-reacting substance and vasoactive peptides. These substances cause vasodilation, increased capil- lary permeability and smooth-muscle contraction —the features of allergic airways disease.

The atopic syndrome

The atopic syndrome is a hereditary disorder of variable penetrance. Subjects are particularly susceptible to the development of IgE-mediated allergic reactions manifested by:

1 infantile eczema;

2 allergic asthma;

3 nasal and conjunctival allergy.

Allergens The allergens responsible for nasal allergy are inhaled and may be:

1 seasonal, e.g. mould spores in autumn, tree and grass pollen in spring;

2 perennial,e.g.animal dander (especially cats),house dust mite .

SYMPTOMS

1 Watery rhinorrhoea.

2 Sneezing attacks —often violent and prolonged.

3 Nasal obstruction.

4 Conjunctival irritation and lacrimation.

In taking a history, it is important to relate the onset of the symptoms to exposure to the suspected allergen.

SIGNS:

1 The nasal mucosa is oedematous and usually pale or violet in colour.

2 There is excessive clear mucus within the nose, and this usually contains an increased number of eosinophils.

3 Children may develop a transverse nasal skin crease from rubbing the nose —the allergic salute.

INVESTIGATIONS

1 The importance of a history of symptoms related to allergen exposure cannot be overemphasized.

2 Skin testing interpreted in relation to the history is valuable. The skin of the forearm is pricked with a needle through a dilute solution of the relevant allergen; a positive response is a central weal with surrounding erythema.

3 RAST (radio-allergo sorbent test) measures allergen-specific IgE and has the advantage of being performed on a blood sample. It is especially useful in children for whom skin tests are unsuitable.

4 A high total IgE level is a useful indication of the presence of atopy.

TREATMENT

1 Avoidance of contact with the allergen may be possible, especially in the case of domestic pets.

2 Antihistamines are useful in acute episodes but tolerance develops. The latest generation of antihistamines (H1 receptor antagonists) do not produce drowsiness.

3 Vasoconstrictor nasal drops provide temporary relief but are not advis- able, as prolonged use leads to chronic rhinitis medicamentosa.

4 Sodium cromoglycate (Rynacrom) applied to the nose 4–6 times daily as prophylaxis is particularly suitable for children.

5 Topically applied steroid preparations (beclomethasone, flunisolide) are probably the most effective treatment of nasal allergy. Systemic effects of steroid therapy are absent but such treatment is not advisable in young children.

6 Desensitization by administration of increasing dosages of allergen is no longer widely practised, as it is of little benefit in most cases and carries the risk of anaphylaxis.

7 If gross hypertrophy of the nasal mucosa has occurred, surgical reduc- tion by diathermy or laser may be beneficial.

NON-ALLERGIC VASOMOTOR RHINITIS

Eosinophilic vasomotor rhinitis

Eosinophilic vasomotor rhinitis is associated with the formation of nasal polyps, aspirin sensitivity and asthma.The symptoms are similar to allergic rhinitis with watery rhinorrhoea and sneezing, but the type I allergic re- sponse is not involved.There may, however, be increased nasal sensitivity to irritants such as perfume and tobacco smoke. Although a blood count may not always show a raised eosinophil count, such cells will be present in nasal secretions.

TREATMENT

Treatment is by topical nasal steroid (e.g. beclomethasone) or systemic antihistamines.

Nasal polyps

Nasal polyps occur in nonallergic eosinophilic rhinitis rather than in allergic rhinitis. They cause nasal obstruction, sometimes with a ball-valve effect, nasal discharge, and are usually bilateral.They have a tendency to recur.

 Diagnosis is made by examination of the nose. Polyps are yellowish-grey or pink, smooth and moist .They are pedunculated and move on probing. It is a common error to see the inferior turbinate and mistake it for a polyp —do not be caught out. Nasal polyps do not occur in children except in the presence of cystic fibrosis. An apparent polyp in a baby is probably a nasal glioma or a nasal encephalocoele. Histologically, nasal polyps consist of a loose oedematous stroma infiltrated by inflammatory lymphocytes and eosinophils and covered by respiratory epithlium.

TREATMENT

1 Nasal polyps may shrink with topical steroid therapy but will not usual- ly disappear.

2 Nasal polypectomy is performed under local or general anaesthetic, the polyps being removed with grasping forceps or by a powered microdebrider.

3 Endoscopic ethmoidectomy may be required for recalcitrant cases

4 Short courses of steroids are useful in severe cases.

 Antrochoanal polyps

An antrochoanal polyp is usually solitary, arising within the maxillary antrum, extruding through the ostium and presenting as a smooth swelling in the nasopharynx. Such a polyp may extend below the soft palate and be several centimetres in length.

Treatment consists of avulsion from within the nose and delivering the polyp, usually per-orally. Non-eosinophilic vasomotor rhinitis Non-eosinophilic vasomotor rhinitis is less common than its eosinophilic counterpart and is thought to be due to autonomic dis- turbance of vasomotor tone, with excessive parasympathetic activity 

NON EOSINOPHILIC VASOMOTOR RHINITIS

AETIOLOGY

In most cases no specific cause is found but certain conditions may be relevant.

1 Drug treatment: certain antihypertensive drugs, particularly ganglion blockers; contraceptive pills; vasodilator drugs.

2 Hormonal disturbance: pregnancy; menopause; hypothyroidism.

3 Congestive cardiac failure.

4 Anxiety state.

5 Occupational irritants, e.g. ammonia, sulphur dioxide.

6 Smoking.

SYMPTOMS

1 Watery rhinorrhoea.

2 Nasal obstruction —varies from side to side and is worse on lying down, especially in the undermost nostril.

3 Sneezing attacks.

Symptoms are often precipitated by change of temperature, bright sunlight, irritants (e.g. tobacco smoke) or alcohol ingestion.

SIGNS

1 There may be none. Usually the nasal mucosa is dusky and congested, the engorgement of the inferior turbinates leading to the nasal obstruction.

2 There may be excessive secretions in the nose.

3 The symptoms are often more severe than examination of the nose would suggest.

TREATMENT

1 Often no treatment is required because the symptoms are minor and no significant abnormality is found on examination.

2 Exercise, by increasing sympathetic tone, often provides relief.

3 Sympathomimetic drugs, e.g. 15mg pseudoephedrine t.d.s., are often helpful but tolerance occurs rapidly (tachyphylaxis).

4 The watery rhinorrhoea may respond to topical nasal ipratropium spray, but this has no effect on nasal blockage.

5 If hypertrophy of the nasal mucosa has occurred, surgical reduction by diathermy, cryosurgery or amputation is of value.

6 Vasoconstrictor nose drops, such as oxymetazoline, should be condemned. Such strictures apply also to the use of cromoglycate/ vasoconstrictor combinations. Although providing temporary relief, re- bound hyperaemia occurs, causing the need for further dosage —a downhill spiral to rhinitis medicamentosa will result. Such a habit is hard to break, and the abuse of nasal vasoconstrictor drops is unfortunately widespread and often initiated by medical advisers.There seems to be little justification for the continued availability of this form of therapy