This is the other common form of allergic rhinitis. It is the non-seasonal form and there is usually sensitivity to allergens present in the environment throughout the year, e.g. house dust mites, fungal spores or animal danders. In South Africa the long duration of the grass season may account for prolonged symptoms in sensitive people. Although perennial allergic rhinitis resembles seasonal allergic rhinitis, separate consideration of the perennial form can better clarify this complex condition, particularly with respect to diagnosis, management and complications. B.1. Symptoms
The symptoms of perennial allergic rhinitis often commence before the age of 10 years, but are not always noted by parents. Eye symptoms and itching do not always occur. Sneezing and watery nasal discharge are troublesome and there is intense nasal obstruction. Associated maxillary sinusitis is very common. Nasal obstruction may be associated with malaise, headaches, disturbed sleep and mouth breathing. The latter leads to very dry lips. Patients are often thirsty and may wake at night for a drink of water. Postnasal mucous drip is usually present. A common manifestation is the “allergic salute” where the nose is pushed upwards or sideways (Plate 8 on page 132) to try and clear the nasal obstruction. After a while this produces a characteristic transverse crease across the nose where the cartilaginous part of the nose meets the bony part. This is the so-called “allergic crease” (Plate 9 on page 133). Other mannerisms including twitching of the nose may also occur. Nasal obstruction is also associated with a bluish discolouration of the orbital-palpebral grooves beneath the lower eyelids known as “allergic shiners” (Plate 10 on page 133). This is thought to be due to venous stasis resulting from the mucosal oedema of the nose and sinuses. The lower eyelids are often slightly puffy as well and several skin creases may be noted. These are known as Denne’s lines. B.2. Diagnosis
This is based on the same criteria used to diagnose seasonal allergic rhinitis. The history is most helpful in disclosing perennial symptoms and suspected allergens. On examination, the typical pale allergic facies (Plate 11 on page 134) will be noted in many cases together with “shiners” and often a nasal crease. Mouth breathing is commonly noted. There is usually severe swelling of the nasal mucous membrane and lower turbinates with secretions which range from clear to an opaque whitish colour. Textbooks often describe the colour of the mucous membrane as grey or greyish pink but this is variable especially if the condition is chronic. In chronic cases the mucous membrane may have a dark red colour which may make clinical diagnosis difficult. Speech may have a nasal quality and there may be loss of taste and smell. In children affected early in life, narrowing of the arch of the palate and dental malocclusion can develop. Associated secretory otitis media occurs as a result of chronic oedema involving the openings of the eustachian tubes. Skin tests or RAST tests are helpful in confirming the diagnosis by showing positive reactions to perennial allergens in most cases. Nasal smears stained with Hansel’s stain usually show the presence of clumps of eosinophils. Total serum IgE measurement may help to differentiate allergic from non-allergic rhinitis. In approximately 40% of children with perennial allergic rhinitis, total opacity of the maxillary sinuses will be found on radiography. Significant mucosal swelling will be found in another 20%. This investigation is of value in assessing the patient’s condition, but it is seldom necessary to drain the sinuses surgically. B.3. Treatment
Intensive treatment is not required in mild cases. Energetic treatment is reserved for more severe cases, especially if associated complications such as secretory otitis media are present. B.4. Specific Measures
Inhalant allergens.
The most common causes of perennial allergic rhinitis are house dust, house dust mite and dander from cats and dogs. Treatment should initially be directed towards organising a dust-free bedroom. There are many programmes available for carrying out this measure, much of which is based on a common-sense approach. If really necessary, cats or dogs may have to be removed from the house. Where a food is suspected of causing allergic rhinitis the symptoms usually date from infancy and do not vary with the season. Cow’s milk is by far the commonest offender and a careful milk-free diet works wonders in many infants with nasal allergy. Avoidance of irritants.
Non-allergenic factors such as cigarette smoke, chalk dust, aerosol deodorants, hair sprays and sawdust will irritate the sensitive nasal mucous membrane to a great extent. Exposure to these irritants as well as to heavily chlorinated swimming pools is best avoided. B.5. Symptomatic Treatment
Oral Antihistamines or antihistamine-decongestants are probably not as effective as in cases of seasonal allergic rhinitis. It is still worthwhile trying the non-sedating antihistamines especially during times of the year when symptoms are more marked. Sodium cromoglycate (Rynacrom) is not as effective in perennial allergic rhinitis as it is in the seasonal form. The reason for this is not clear but the excessive nasal obstruction may not allow adequate delivery of the drug to the affected nasal mucous membrane. Topical steroid e.g. Beclomethasone dipropionate (Beconase) is very effective in the treatment of even the most resistant cases of perennial allergic rhinitis. Many patients prefer an aqueous form of nasal spray with its gentler spray. The newer steroid nasal sprays such as Fluticasone (Flixonase) and Budesonide (Rhinocort) are very effective, safe and well tolerated. Depot steroid therapy and oral steroids certainly afford relief in resistant cases. The risk of adrenal suppression and other side-effects such as osteoporosis must always be borne in mind especially where potent long-acting preparations are used. If steroid therapy is required, a short-acting preparation such as prednisone is recommended e.g. for a student who has to study for examinations. Surgical treatment.
Varying degrees of septal deviation occur in about one-third of patients with perennial allergic rhinits. Mild septal deviation without unilateral congestion need not be corrected. In severe cases, especially in the patient over 16 years of age, surgical correction will produce a more patent nasal airway. Diathermy, cautery and submucous resection to improve airway patency and reduce mucosal swelling may produce temporary relief, but the symptoms may recur and be more difficult to deal with in the future. Immunotherapy.
This may be considered to be the definitive treatment for perennial allergic rhinitis. Owing to the length of treatment, which should not be less than 3 years, immunotherapy is best used in patients whose symptoms are inadequately controlled in spite of appropriate environmental measures and symptomatic therapy. |
