Are eosinophils elevated in a person with constant rhinorrhea?

From the Guidelines

Eosinophils may be elevated in a person with constant rhinorrhea, but this depends on the underlying cause of the nasal discharge. Allergic rhinitis, which often causes persistent rhinorrhea, typically features elevated eosinophil counts in both nasal secretions and sometimes in peripheral blood, as noted in the study by 1. When rhinorrhea is caused by allergic inflammation, the body releases histamine and other inflammatory mediators that attract eosinophils to the nasal mucosa as part of the immune response to allergens. However, if the constant rhinorrhea is due to non-allergic causes such as viral infections, vasomotor rhinitis, or medication side effects, eosinophil counts may remain normal. To determine if eosinophils are elevated, a nasal smear examination (nasal cytology) can be performed, which often shows increased eosinophils in allergic conditions, as discussed in 1. Some key points to consider include:

• The presence of eosinophils in nasal smears is not necessary for routine use in diagnosing allergic rhinitis, but may be useful when the diagnosis is in question, as stated in 1.
• Nasal biopsy for eosinophils may be more accurate than nasal smears, as mentioned in 1.
• The number of eosinophils in nasal smears correlates with the severity of perennial allergic rhinitis in children, as found in 1.
• Elevated eosinophils typically suggest that anti-inflammatory treatments like intranasal corticosteroids or antihistamines would be beneficial, as implied by the studies 1. It is essential to identify the underlying cause of rhinorrhea to provide appropriate treatment, as the presence of eosinophils can guide treatment decisions, as noted in 1.

From the FDA Drug Label

The effect of SINGULAIR on eosinophils in the peripheral blood was examined in clinical trials In patients with asthma aged 2 years and older who received SINGULAIR, a decrease in mean peripheral blood eosinophil counts ranging from 9% to 15% was noted, compared with placebo, over the double-blind treatment periods. In patients with seasonal allergic rhinitis aged 15 years and older who received SINGULAIR, a mean increase of 0. 2% in peripheral blood eosinophil counts was noted, compared with a mean increase of 12.5% in placebo-treated patients, over the double-blind treatment periods; this reflects a mean difference of 12. 3% in favor of SINGULAIR.

The question of whether eosinophils are elevated in a person with constant rhinorrhea is not directly answered by the information provided about the effect of montelukast on eosinophil counts in patients with asthma or seasonal allergic rhinitis. However, it can be noted that:

• In patients with asthma, montelukast decreased eosinophil counts.
• In patients with seasonal allergic rhinitis, montelukast resulted in a lower increase in eosinophil counts compared to placebo. It is not possible to draw a conclusion about the elevation of eosinophils in a person with constant rhinorrhea based on the provided information 2.

From the Research

Eosinophil Levels in Constant Rhinorrhea

• Constant rhinorrhea can be a symptom of various conditions, including allergic rhinitis and non-allergic rhinitis 3, 4, 5.
• Eosinophils play a critical role in type 2 inflammation, which is characteristic of allergic rhinitis 6, 7.
• Studies have shown that patients with perennial allergic rhinitis (PAR) tend to have higher blood eosinophil levels and more severe nasal and ocular symptoms compared to those with non-allergic rhinitis (NAR) or seasonal allergic rhinitis (SAR) 6.
• Blood eosinophil levels were found to be significantly higher in SAR patients during the pollen season compared to the non-pollen season, and pollen concentrations were positively correlated with systemic and local eosinophil levels 6.
• Patients with high blood eosinophil levels tend to have more severe overall nasal and ocular symptoms, and a higher rate of comorbid asthma and allergic conjunctivitis 6.

Relationship Between Eosinophils and Rhinorrhea

• The distribution of eosinophils in patients with different subtypes of rhinitis and the effect of allergen exposure on them remain understudied 6.
• Eosinophils themselves cannot fully explain the underlying pathophysiology of chronic rhinosinusitis, a complex disorder that may involve constant rhinorrhea 7.
• Further longitudinal cohort studies are needed to better analyze the influence of eosinophil levels on the clinical traits of allergic rhinitis and other conditions characterized by constant rhinorrhea 6.