Australian Doctor Australia Doctor 18th August 2017 | Page 24

How to Treat – Allergic rhinitis

from page 22 condition , resulting from abuse of intranasal decongestants is discussed in box 1 . Non-allergic rhinitis and sinusitis complete the list of important differential diagnoses to consider at a patient ’ s initial assessment .
Non-allergic rhinitis A number of the important and less rare non-allergic causes of rhinitis are listed in table 3 ; this list is not exhaustive . A systematic approach to their consideration ( in line with the categories in the table ) will save valuable time .
Sinusitis Patients with acute sinusitis may present with some of the features of allergic rhinitis . Age of onset should be taken into account and this alone may favour sinusitis . Acute sinusitis is often accompanied by the characteristic facial pain / pressure sensation and discoloured nasal discharge . Hyposmia / anosmia favours the diagnosis . The investigation and management of sinusitis is not discussed here . However , it is important to note that many of the agents used in the management of allergic rhinitis will be of benefit to patients with sinusitis .
Viral rhinosinusitis Viral rhinosinusitis may present with very similar symptoms to allergic rhinitis . However , the duration of symptoms is often less than two weeks and this condition is associated with the systemic features of viral illness ( such as fever and myalgia ).
Investigation Therapeutic trial A trial of intranasal and / or oral medications is a reasonable and pragmatic step that serves both a diagnostic and therapeutic function . Where allergic rhinitis is the most likely diagnosis based on history and physical examination , and other concerning diagnoses have been excluded , appropriate medications can be started and the response to treatment assessed after one month . See Pharmacotherapy for guidance on appropriate initial agents .
Important feature of the history General
Table 2 . History-taking in allergic rhinitis ( AR ) Significance
When did the symptoms first start ? Persistent ( previously perennial ), AR is more common in preschool-aged children . Intermittent AR with a seasonal variance is more common in school-aged children and young adults . Onset in later life should prompt consideration of a non-allergic cause of rhinitis .
Do the symptoms occur predominantly at certain times of the year or all year round ?
In general , grasses pollinate late-spring to early-summer and trees do so from late-winter to earlyspring .
What indoor allergens is the patient exposed to ?
Understanding a patient ’ s housing and workplace conditions will reveal potential offending allergens .
What is the patient ’ s occupation ?
Understanding a patient ’ s housing and workplace conditions will reveal potential offending allergens .
Is there a family history of atopy ?
A family history of atopy and in particular AR is the best-established risk factor for the development of AR .
What is the impact of symptoms ?
AR can have a significant , negative impact on sleep quality and other quality of life domains .
What medications have been tried to date ? How regularly and for how long ?
Failure of response to particular medications helps direct initial pharmacotherapy . Failure of response to an optimal regimen of medications may suggest an alternative cause . Prolonged use of nasal decongestants can lead to rebound rhinitis ( see rhinitis medicamentosa ).
What other medications does the patient take regularly ?
Drug-induced rhinitis ( see differential diagnosis ) may mimic allergic rhinitis .
Symptoms
Classification
Classifying AR helps direct initial pharmacotherapy .
What is the most troublesome symptom ?
The predominant symptom may potentially direct treatment .
What is the character and source of nasal discharge ?
Consider ‘ red flags ’.
Is there a diurnal variation to symptoms ?
Sneezing and nasal obstruction are worse in the morning in 70 % of patients with AR .
Is there hyposmia or anosmia ?
Mild hyposmia is not rare in symptomatic AR ; however , anosmia or more severe hyposmia should
prompt consideration of alternative diagnosis .
Is post-nasal drip or chronic cough a feature ?
This question may reveal acute or chronic sinusitis as a concomitant or alternative diagnosis ( see
differential diagnosis ).
Are there symptoms consistent with asthma or bronchial hypersensitivity ?
The close relationship between AR and asthma is discussed later . History-taking in a patient presenting with AR should aim to determine the presence and degree of concomitant asthma .
Source : AIHW and Hu W , et al . Allergic rhinitis : practical management strategies . Australian Family Physician 2008 ; 37:214-20 .
Box 1 . Rhinitis medicamentosa
RHINITIS medicamentosa , also called chemical rhinitis or rebound rhinitis , results from the prolonged ( more than five days ) use of intranasal decongestants ( and some other medications ). The patient ’ s history of medication use will reveal the diagnosis . It is characterised by nasal congestion without rhinorrhoea or sneezing and is the result of ‘ rebound ’ interstitial oedema . Histologically , it is associated with nasociliary loss , epithelial oedema , goblet cell hyperplasia and inflammatory cell infiltration . 13
Management involves :
• Immediate cessation of intranasal decongestants or other offending agent / s
• Education regarding the appropriate ( short-term ) use of these agents
• Administration of intranasal corticosteroids ( if necessary )
• Treatment of the allergic rhinitis with more appropriate pharmacotherapy
Table 3 . Some of the causes of non-allergic rhinitis Category
Condition Rhinitis medicamentosa See box 1 Mechanical
Septal deviation Adenoid / turbinate hypertrophy Foreign bodies Choanal atresia
Neoplastic
Nasopharyngeal tumour Infectious Rhinosinusitis ( see later )
Immunologic / inflammatory Nasal polyposis Granulomatous diseases Sjögren ’ s syndrome
Medication-induced Rhinitis medicamentosa NSAIDs / aspirin Antihypertensives Cocaine-sniffing
Physiologic
Disorders associated with ciliary dyskinesia ( cystic fibrosis , primary ciliary dyskinesia )
Hormonal
Hypothyroidism Pregnancy Oral contraceptives Exercise-induced
Idiopathic Vasomotor rhinitis
Laboratory studies Skin-prick testing Properly performed skin-prick testing is the gold standard in the diagnosis of allergic rhinitis . A positive skin prick test implies first , the presence of antibodies to a given allergen and next , an immune response to antigen challenge , diagnostic of atopy .
Skin-prick testing is relatively easily performed in the outpatient setting and can be used from infancy to advanced age .
Pre-test considerations Several conditions ( widespread eczema , urticaria , spinal cord injury and other neurological conditions ) and medications ( particularly oral antihistamines , imipramine , clonidine and phenothiazines ) affect the diagnostic utility of skin-prick testing .
A comprehensive practitioner ’ s manual is produced by the Australasian Society of Clinical Immunology and Allergy ( ASCIA ) ( see Further reading ) that details pre-test considerations
, discusses causes of falsenegative and false-positive results , and describes the protocols of skin prick testing .
Interpretation Interpretation of skin-prick test results must be made in the context of the patient ’ s history , examination and clinical disease . A positive skinprick test to aeroallergens with a consistent history and examination is diagnostic of allergic rhinitis . In interpreting test results both in the laboratory and in the rooms , the causes of false-positive and falsenegative results should be considered .
Other allergen challenge testing Other allergen challenge tests ( patch test , intradermal allergen challenge , scratch tests ) are not routinely used
to diagnose allergic rhinitis .
RAST The radioallergosorbent test ( RAST ) measures serum-specific IgE against antigens . Its reliability is likewise affected by the quality of the allergens used . The positive predictive value of serum-specific IgE is more than 85 %. 8 This investigation will determine whether a patient has IgE against a specific agent , but this does not necessarily equate with clinical disease , and must be interpreted in light of the patient ’ s history and examination .
IgE quantification Serum-total IgE is elevated in parasitic and other allergic diseases , and this investigation plays no role in the routine investigation of isolated allergic rhinitis .
Clinical feature
Unilateral discoloured , offensive or bloody discharge in a child
Unilateral discoloured , offensive or bloody discharge in an adult
Nasal polyps in a child
Unilateral watery discharge without nasal obstruction
Unilateral nasal obstruction ( unless due to unilateral congestion due to septal deviation )
Moderate to severe hyposmia / anosmia
Table 4 . Red flags Action
Consider and look for a nasal foreign body
Perform or refer for nasendoscopy to exclude malignancy
Refer for sweat test to exclude cystic fibrosis
Consider cerebrospinal fluid leak , particularly in the setting of trauma or recent nasal surgery . Samples can be sent for beta2-transferrin testing for diagnosis , but referral to an ENT surgeon or neurosurgeon should not be delayed
Prompt referral to an ENT surgeon should be made to exclude malignancy and other causes
Complete anosmia is not explained exclusively by allergic rhinitis and patients should be referred for imaging and further assessment
Mucosal challenge At present , direct nasal mucosal challenge is used exclusively in clinical
trials and not as an investigative tool in clinical practice .
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