Approach
The presenting symptoms of NAR are indistinguishable from other forms of chronic rhinitis and include:
Bilateral nasal congestion
Bilateral postnasal drainage
Other upper respiratory symptoms such as sneezing and rhinitis
Bilateral ear fullness
Symptoms on most days.
Key negatives in the history can help distinguish NAR syndromes from allergic rhinitis:
Family history of allergies makes NAR less likely
Symptoms do not fluctuate seasonally in NAR: specifically, triggers are not worse outdoors during a specific pollen season in response to airborne allergens
Symptoms are not exacerbated by cat or dog exposure.
Exacerbation of symptoms in response to perfumes/fragrances, hairspray, potpourris, tobacco and wood smoke, changes in temperature, and barometric changes can be seen in NAR as well as in allergic rhinitis.[5]
It has previously been reported, based on a self-administered questionnaire, that a patient had a 96% pre-test probability of receiving a physician diagnosis of non-allergic vasomotor rhinitis if they had onset of symptoms later in life (age >35), no family history of allergies, no symptoms with seasonality or cat exposure. However, non-allergic triggers included temperature changes, diesel and car exhaust, tobacco smoke, perfumes and fragrances, incense, cleaning products, newsprint, hairspray, and alcoholic beverages, spicy foods, or eating.[9] However, not all patients with NAR exhibit symptoms in response to non-allergic triggers.
A more recent study was performed to determine whether reclassification of physician-diagnosed rhinitis subtypes based on an irritant index questionnaire (IIQ) identified rhinitis patients with different clinical characteristics. The IIQ demonstrated good internal consistency and cross-validation. After reclassification, 48% and 52% of patients with physician-diagnosed allergic rhinitis (n=533) were categorized as having low-burden allergic rhinitis and high-burden allergic rhinitis, respectively, whereas 64% and 36% of NAR patients (n=123) were categorized as having low-burden NAR and high-burden NAR, respectively. Reclassified high-burden allergic rhinitis and high-burden NAR patients were more likely to have a physician diagnosis of asthma and a greater number of self-reported rhinitis symptoms and perennial symptoms with seasonal exacerbations than reclassified low-burden allergic rhinitis and low-burden NAR patients, respectively (P <0.01). The IIQ resulted in significant reclassification of physician-diagnosed rhinitis patients into different diagnostic categories with unique clinical characteristics.[18]
Exam findings
Findings are similar in perennial allergic and NAR syndromes and include:
Swollen and beefy red nasal turbinates
Scant mucus
Cobblestoning of posterior pharynx
Retraction of tympanic membranes.
Nasal creases and raccoon eyes correlate with venous congestion, and mouth breathing with nasal congestion, so although they are considered more characteristic of allergic disease, they can also be seen in non-allergic chronic rhinitis.
Early imaging for structural problems
Normally, imaging is not indicated during initial evaluation for NAR. However, the following should prompt consideration of early imaging to rule out structural problems or tumor:
Unilateral symptoms
Constitutional symptoms such as weight loss
Fixed firm lymphadenopathy
History of no response to decongestant medications.
Allergy testing
Allergy must be excluded before a diagnosis of NAR can be made.[3][4] Options are skin prick testing, or serological IgE testing to specific aeroallergens. Seasonal and perennial aeroallergens should be tested.
Skin prick testing:
Tests skin mast cell-bound IgE directly
Is most specific and sensitive
Is less effective if there is a history of dermatography, history of severe eczema, or the patient is taking a histamine blocker, ACE inhibitors, or tricyclic antidepressants
May be used in the presence of high-dose corticosteroid use, despite possible attenuation of the skin testing responses.
Serologic IgE testing:
Enzyme-linked immunosorbent assay-based test has replaced the traditional radioallergosorbent technique
Is more expensive than skin prick testing
May give a false negative out of season because serum IgE has a 2.5-day half-life (checking specific IgE for spring tree pollen in the fall or winter could result in lower levels of specific IgE)
May give a nonspecific response if total IgE levels are very high.
NAR should exclude entopic rhinitis where patients have negative skin tests but localized specific IgE antibodies in nasal secretions.
Nasal eosinophil testing
Once the diagnosis of NAR is established, nasal eosinophil smears are indicated to help differentiate the subtypes of NAR into a non-allergic inflammatory rhinitis condition from a non-allergic, non-inflammatory condition. False negatives are common and may result from interference as simple as a recent nasal saline irrigation or a long session of swimming. To verify the presence or absence of eosinophils, repeat nasal smears on successive days while patients are off intranasal corticosteroids and antihistamines should be considered. Other methods such as nasal scrapings have been noted to yield positive results more consistently.[19]
Nasal provocation
Nasal provocation using a non-allergic rhinitis chamber has been found to reproducibly elicit symptoms in response to cold dry air and cold dry air followed by warm air in NAR patients.[20]
Imaging
Sinus computed tomography (CT) is not required in evaluation for NAR but is indicated when structural disease, including osteomeatal complex disease or sinusitis, is suspected. The most useful analysis will be obtained by specifying a noncontrast CT scan of the paranasal sinuses to rule out osteomeatal complex disease and other structural anomalies.
Indications for sinus CT include:
Unresponsiveness to acute trial of decongestants
Unresponsiveness to second-line therapy with nasal saline, nasal corticosteroids, and nasal azelastine in combination
Multiple courses of antibiotics for possible sinusitis
Red flag symptoms or findings: unilateral symptoms, bloody rhinorrhea, or constitutional findings suggestive of malignancy such as cachexia, fixed lymphadenopathy, and weight loss.
Most patients with NAR will have normal CT scan of the sinuses; however, chronic sinusitis and osteomeatal complex disease can be an unrecognized complication of NAR. A CT scan in those individuals refractory to treatment will exclude structural abnormalities.
Nasal endoscopy
May be considered if there is throat swelling, hoarseness, or suspicion of a mass on physical exam. This can be most useful for direct visualization of vocal cords. However, the sinus CT specified to rule out osteomeatal complex disease provides superior structural information in most cases. Nasal endoscopy is therefore not routinely recommended unless suspicion for another diagnosis is high.
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