Published: September 2026
Medically reviewed by:
Gary Falcetano, PA-C, AE-C
Nasal and sinus symptoms are common during cold and flu season. If they persist or keep recurring, infection may not be the only consideration. Allergic disease, including allergy associated with indoor allergens, may also contribute to respiratory symptoms.¹
When the cause remains unclear, consider allergy in the differential diagnosis. ImmunoCAP™ Specific IgE tests can help identify IgE sensitization when interpreted in the context of the patient’s medical history. The results can support the diagnostic evaluation of allergic and nonallergic conditions.²
What symptoms overlap between a cold, sinus infection and indoor allergy?
Overlapping respiratory symptoms can make it difficult to distinguish between these conditions.3-5
| Symptoms/condition | Cold | Sinus infection | Indoor allergy |
Nasal congestion |
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Runny nose |
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Cough |
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Sneezing |
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Itchy, watery eyes |
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Headache |
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| Sinus pressure/facial discomfort | |||
| May persist or recur with exposure |
= symptom may occur; symptoms alone may not clearly differentiate these conditions
When should you consider allergy?
Because symptoms can overlap, the clinical pattern may be more informative than any single symptom.
Consider whether symptoms:
- Persist or recur beyond a typical respiratory illness
- Show a seasonal pattern or are associated with specific environmental or allergen exposures
- Include itchy, watery eyes or other features suggestive of allergic disease
- Occur alongside asthma or a history of allergic disease
Infection and allergy can coexist. A viral infection may be present while underlying allergic disease adds to the patient’s overall respiratory burden.1 When allergy is suspected, consider targeted specific IgE testing to provide objective evidence of allergen sensitization.2
Which indoor allergen exposures should you consider?
If allergy is part of the differential diagnosis, consider how symptoms relate to the patient’s environment.
Relevant indoor allergens may include house dust mite, cat and dog dander, molds and cockroach allergens. Symptoms associated with pets, house dust, upholstered furniture, wall-to-wall carpeting or damp areas may support further evaluation for indoor allergy.
Consider whether symptoms worsen in a particular environment, recur after a similar exposure or improve when the patient is away from the suspected trigger. These patterns can help identify which allergens are most relevant to investigate and support a more targeted approach to specific IgE testing.
Consider the whole airway
Recurrent nasal or sinus symptoms may not be limited to the upper airway. When cough or wheeze is also present, consider lower-airway involvement, as allergic disease, viral illness and asthma can affect the respiratory tract.6
When can ImmunoCAP specific IgE testing add clarity?
Clinical history remains central to diagnosis, but symptoms alone may not distinguish allergic from nonallergic causes.2 When allergy is suspected, a targeted specific IgE blood test can provide objective evidence of allergic sensitization.
ImmunoCAP™ allergy solutions define the standard for in vitro allergy diagnostics, delivering clinically proven, reproducible results that enable confident allergy diagnosis and management.3,7-10
ImmunoCAP Specific IgE tests provide quantitative results that can help:
- Rule in or rule out allergic sensitization
- Identify sensitization to clinically relevant allergens
- Support more informed diagnosis and treatment planning²
- Inform appropriate management and help reduce unnecessary treatment
How should specific IgE testing be selected and interpreted?
Focus testing on allergens relevant to the patient’s symptoms and exposures. A positive specific IgE result indicates sensitization and should be interpreted alongside the clinical picture. When sensitization aligns with persistent or recurrent symptoms, the results can help inform more targeted care decisions.²
Frequently asked questions
Consider specific IgE testing when the clinical history suggests allergy may be contributing to persistent or recurrent respiratory symptoms. This may include patients whose symptoms are linked to relevant exposures, recur in a consistent pattern or persist beyond a typical respiratory infection.
A positive specific IgE result indicates sensitization and should be interpreted alongside the clinical picture.²
A negative result can help rule out sensitization to the allergen tested. Interpret the result in the context of the patient’s clinical history and exposures to determine whether other allergic or nonallergic causes should be considered.2
To order ImmunoCAP Specific IgE tests, getting a thorough patient history and a list of symptoms is a key first step. For example, if a history and symptoms indicate a potential respiratory allergy, you can order a respiratory profile that will include indoor and outdoor allergens. To see which tests are available from your local laboratory, search the Lab Ordering Guide.
Order a regional respiratory profile*
*The ImmunoCAP profile is not an FDA-cleared product and is not placed on the market by Thermo Fisher Scientific. It is a laboratory-defined testing panel, consisting of individually FDA-cleared ImmunoCAP™ allergen products ordered separately by their official product names and article numbers.
