Occupational Rhinitis: Classification, Diagnosis, and Therapeutics

Nonallergic Rhinopathy: A Comprehensive Review of Classification, Diagnosis, and Treatment

Chronic nonallergic rhinitis syndromes encompass various conditions, of which vasomotor rhinitis is the most common form, representing approximately 80% of patients, also referred to as nonallergic rhinopathy (NAR), nasal hyperreactivity, neurogenic rhinitis, or idiopathic rhinitis. Expert panels have recommended replacing vasomotor rhinitis terminology because it is more descriptive of this condition that is characterized by symptoms triggered by chemical irritants and weather changes through chemosensors, mechanosensors, thermosensors, and/or osmosensors activated through different transient receptor potential calcium ion channels. Elucidating the specific role of transient receptor potential vanilloid 1, triggered by capsaicin, has been an important advancement in better understanding the pathophysiology of NAR because it has now been shown that downregulation of transient receptor potential vanilloid 1 receptors by several therapeutic compounds provides symptomatic relief for this condition. The classification of NAR is further complicated by its association with allergic rhinitis referred to as mixed rhinitis, which involves both immunoglobulin E-mediated and neurogenic mechanistic pathways. Comorbidities associated with NAR, including rhinosinusitis, headaches, asthma, chronic cough, and sleep disturbances, underscore the need for comprehensive management. Treatment options for NAR include environmental interventions, pharmacotherapy, and in refractory cases, surgical options, emphasizing the need for a tailored approach for each patient. Thus, it is extremely important to accurately diagnose NAR because inappropriate therapies lead to poor clinical outcomes and unnecessary health care and economic burdens for these patients. This review provides a comprehensive overview of NAR subtypes, focusing on classification, diagnosis, and treatment approaches for NAR.

Allergic Rhinitis: A Review

Importance

Allergic rhinitis affects an estimated 15% of the US population (approximately 50 million individuals) and is associated with the presence of asthma, eczema, chronic or recurrent sinusitis, cough, and both tension and migraine headaches.

Observations

Allergic rhinitis occurs when disruption of the epithelial barrier allows allergens to penetrate the mucosal epithelium of nasal passages, inducing a T-helper type 2 inflammatory response and production of allergen-specific IgE. Allergic rhinitis typically presents with symptoms of nasal congestion, rhinorrhea, postnasal drainage, sneezing, and itching of the eyes, nose, and throat. In an international study, the most common symptoms of allergic rhinitis were rhinorrhea (90.38%) and nasal congestion (94.23%). Patients with nonallergic rhinitis present primarily with nasal congestion and postnasal drainage frequently associated with sinus pressure, ear plugging, muffled sounds and pain, and eustachian tube dysfunction that is less responsive to nasal corticosteroids. Patients with seasonal allergic rhinitis typically have physical examination findings of edematous and pale turbinates. Patients with perennial allergic rhinitis typically have erythematous and inflamed turbinates with serous secretions that appear similar to other forms of chronic rhinitis at physical examination. Patients with nonallergic rhinitis have negative test results for specific IgE aeroallergens. Intermittent allergic rhinitis is defined as symptoms occurring less than 4 consecutive days/week or less than 4 consecutive weeks/year. Persistent allergic rhinitis is defined as symptoms occurring more often than 4 consecutive days/week and for more than 4 consecutive weeks/year. Patients with allergic rhinitis should avoid inciting allergens. In addition, first-line treatment for mild intermittent or mild persistent allergic rhinitis may include a second-generation H1 antihistamine (eg, cetirizine, fexofenadine, desloratadine, loratadine) or an intranasal antihistamine (eg, azelastine, olopatadine), whereas patients with persistent moderate to severe allergic rhinitis should be treated initially with an intranasal corticosteroid (eg, fluticasone, triamcinolone, budesonide, mometasone) either alone or in combination with an intranasal antihistamine. In contrast, first-line therapy for patients with nonallergic rhinitis consists of an intranasal antihistamine as monotherapy or in combination with an intranasal corticosteroid.

Conclusions and Relevance

Allergic rhinitis is associated with symptoms of nasal congestion, sneezing, and itching of the eyes, nose, and throat. Patients with allergic rhinitis should be instructed to avoid inciting allergens. Therapies include second-generation H1 antihistamines (eg, cetirizine, fexofenadine, desloratadine, loratadine), intranasal antihistamines (eg, azelastine, olopatadine), and intranasal corticosteroids (eg, fluticasone, triamcinolone, budesonide, mometasone) and should be selected based on the severity and frequency of symptoms and patient preference.

Occupational rhinitis

Occupational rhinitis (OR) has so far received little attention even though it shares common pathophysiological features and trigger factors and is closely associated with occupational asthma (OA). Work-related exposure to certain substances, such as animal dander, is considered to be the main factor for the development of OR. The new EAACI definition of OR stresses the causal relationship between workplace exposure and onset of rhinitis symptoms as opposed to previous definitions that mainly focused on a temporal relationship between workplace exposure and occurrence of nasal symptoms. Also, it has been suggested to use the term “work-related rhinitis” for classifying the different forms of rhinitis associated with the workplace. These forms can be subdivided into allergic or non-allergic OR, which is due to causes and conditions related to a particular work environment, as well as work-exacerbated rhinitis, which is defined as a pre-existing rhinitis exacerbated by exposure at the workplace. Even though taking a detailed patient history is especially important when it comes to diagnosing OR, the gold standard for confirming the diagnosis is nasal provocation testing. Best possible symptomatic relief and prevention of development of OA constitute the main therapeutic objectives in OR. Treatment options consist of total avoidance of trigger substances (main goal), reduction of exposure to certain substances, and pharmacotherapy. Furthermore, it is important to note that allergic OR is an occupational disease in Germany (Berufskrankheit No 4301) and needs to be reported to health authorities.

Occupational Rhinitis

There is convincing evidence that tight relationships between the upper and lower airways also apply to the workplace context. Most patients with occupational asthma (OA) also suffer from occupational rhinitis (OR), although OR is 2 to 3 times more common than OA. OR most often precedes the development of OA, especially when high-molecular-weight protein agents are involved, and longitudinal cohort studies have confirmed that OR is associated with an increased risk for the development of OA. The level of exposure to sensitizing agents at the workplace is the most important determinant for the development of IgE-mediated sensitization and OR. Atopy is a risk factor for the development of IgE-mediated sensitization only to high-molecular-weight agents. In workers with work-related rhinitis symptoms, documentation of IgE-mediated sensitization to a workplace agent via skin prick testing or serum specific IgE confirms a diagnosis of probable OR, whereas specific nasal provocation testing in the laboratory remains the reference method to establish a definite diagnosis of OR. Complete avoidance of exposure to the causal agent is the most effective therapeutic option for controlling work-related nasal symptoms and preventing the development of OA. If complete elimination of exposure is expected to induce meaningful adverse socioeconomic consequences, reduction of exposure can be considered as an alternative approach, but it is important to consider the individual risk factors for the development of OA to implement a more personalized management of OR.