Nonallergic rhinitis: Common problem, chronic symptoms
ABSTRACTNonallergic rhinitis can significantly affect a patient’s quality of life. It is difficult to distinguish from allergic rhinitis, but it has different triggers, and its response to treatment can vary. We review its differential diagnosis, causes, and treatment.
KEY POINTS
- When evaluating a patient with rhinitis, a key question is whether it is allergic or nonallergic.
- Identifying triggers that should be avoided is important for controlling symptoms.
- If symptoms continue, then the first-line treatment for nonallergic rhinitis is intranasal steroids.
- Failure of intranasal steroids to control symptoms should prompt a consideration of the many potential causes of rhinitis, and further evaluation and treatment can be tailored accordingly.
A 55-year-old woman has come to the clinic because of clear rhinorrhea and nasal congestion, which occur year-round but are worse in the winter. She reports that at times her nose runs continuously. Nasal symptoms have been present for 4 to 5 years but are worsening. The clear discharge is not associated with sneezing or itching. Though she lives with a cat, her symptoms are not exacerbated by close contact with it.
One year ago, an allergist performed skin testing but found no evidence of allergies as a cause of her rhinitis. A short course of intranasal steroids did not seem to improve her nasal symptoms.
The patient also has hypertension, hypothyroidism, and hot flashes due to menopause; these conditions are well controlled with lisinopril (Zestril), levothyroxine (Synthroid), and estrogen replacement. She has no history of asthma and has had no allergies to drugs, including nonsteroidal anti-inflammatory drugs (NSAIDs.)
How should this patient be evaluated and treated?
COMMON, OFTEN OVERLOOKED
Many patients suffer from rhinitis, but this problem can be overshadowed by other chronic diseases seen in a medical clinic, especially during a brief office visit. When a patient presents with rhinitis, a key question is whether it is allergic or nonallergic.
This review will discuss the different forms of nonallergic rhinitis and their causes, and give recommendations about therapy.
RHINITIS: ALLERGIC OR NONALLERGIC?
While allergic rhinitis affects 30 and 60 million Americans annually, or between 10% to 30% of US adults,1 how many have nonallergic rhinitis has been difficult to determine.
In a study in allergy clinics, 23% of patients with rhinitis had the nonallergic form, 43% had the allergic form, and 34% had both forms (mixed rhinitis).2 Other studies have suggested that up to 52% of patients presenting to allergy clinics with rhinitis have nonallergic rhinitis.3
Over time, patients may not stay in the same category. One study found that 24% of patients originally diagnosed with nonallergic rhinitis developed positive allergy tests when retested 3 or more years after their initial evaluation.4
Regardless of the type, untreated or uncontrolled symptoms of rhinitis can significantly affect the quality of life.
All forms of rhinitis are characterized by one or more of the following symptoms: nasal congestion, clear rhinorrhea, sneezing, and itching. These symptoms can be episodic or chronic and can range from mild to debilitating. In addition, rhinitis can lead to systemic symptoms of fatigue, headache, sleep disturbance, and cognitive impairment and can be associated with respiratory symptoms such as sinusitis and asthma.1
Mechanisms are mostly unknown
While allergic rhinitis leads to symptoms when airborne allergens bind with specific immunoglobulin E (IgE) in the nose, the etiology of most forms of nonallergic rhinitis is unknown. However, several mechanisms have been proposed. These include entopy (local nasal IgE synthesis with negative skin tests),5 nocioceptive dysfunction (hyperactive sensory receptors),6 and autonomic nervous system abnormalities (hypoactive or hyperactive dysfunction of sympathetic or parasympathetic nerves in the nose).7
Does this patient have an allergic cause of rhinitis?
When considering a patient with rhinitis, the most important question is, “Does this patient have an allergic cause of rhinitis?” Allergic and nonallergic rhinitis have similar symptoms, making them difficult to distinguish. However, their mechanisms and treatment differ. By categorizing a patient’s type of rhinitis, the physician can make specific recommendations for avoidance and can initiate treatment with the most appropriate therapy. Misclassification can lead to treatment failure, multiple visits, poor adherence, and frustration for patients with uncontrolled symptoms.
Patients for whom an allergic cause cannot be found by allergy skin testing or serum specific IgE immunoassay (Immunocap/RAST) for environmental aeroallergens are classified as having nonallergic rhinitis.
