Pediatric Allergic Rhinitis Workup

Updated: Nov 15, 2017
  • Author: Jack M Becker, MD; Chief Editor: Harumi Jyonouchi, MD  more...
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Workup

Laboratory Studies

No studies are needed in allergic rhinitis (AR) if the patient has a straightforward history. When the history is confusing, various studies are helpful, including the following:

  • Skin-prick testing: This test is highly sensitive and specific for aeroallergens. However, a false positive reaction can occur without corresponding clinical features, especially when skin mast cells are easily activated by pressure or other physical stimuli.

  • Serum allergen-specific IgE testing: The main limitations are that patients may be sensitive on a molecular level before IgE response is clinically seen on standard skin testing. This may lead to positive results on laboratory tests that are not triggering clinical symptoms. A future advantage is that this may be a first step toward better customization of immunotherapy in the future. [7]

  • Nasal smear: Eosinophils usually indicate allergy. Neutrophils are more indicative of an infectious process, such as sinusitis. This is not used often anymore because of the difficulty in having the test performed. It was used commonly when office laboratories were common.

  • CBC count with differential: A CBC count may reveal an increased number of eosinophils. An eosinophil count within the reference range does not exclude AR; however, an elevated eosinophil count is suggestive of the diagnosis.

  • Immunoglobulin E (IgE): Serum IgE values are not routinely recommended to evaluate atopy. An IgE value within the reference range does not exclude AR; however, an elevated IgE value is suggestive of the diagnosis. Allergen-specific IgE testing, also known as radioallergosorbent test (RAST), which is a blood test that is no longer much in use, can be helpful if a specific allergen is suspected. Screening of a large number of allergens can cause confusion because of the possibility of false positives. This is especially true for IgE food allergy testing. The results of one explorative study found that low levels of serum IgE can be detected from age 6 months. The study suggests that detectable levels of IgE sensitization are associated with present symptoms of eczema, rhinitis, asthma, and food and inhalant allergens and may also be predictive of future allergic symptoms. [8]

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Imaging Studies

Imaging studies are not needed unless sinusitis is suspected, in which case, a limited CT scan of the sinuses (without contrast) is indicated.

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Other Tests

See the list below:

  • Allergen-specific serum IgE for common allergens can be used to identify the patient's triggers. These might include dust mites, cat dander, dog dander, grass pollens, tree pollens, weed pollens, and molds.

  • Foods rarely cause AR, and tests for food allergies are not indicated in patients with AR.

  • Allergen-specific IgE testing for aeroallergens, such as dust mites, cat dander, and dog dander, is almost as sensitive and specific as allergen skin testing.

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Procedures

Skin testing

Skin testing is used to identify the triggering agent. It has high sensitivity and specificity and is the preferred method of quick allergen identification for aeroallergens.

Skin testing is helpful if the allergens can be eliminated from the patient's environment or if the patient can avoid them. It is extremely helpful when patients are unresponsive to standard therapy or are unwilling to acknowledge the trigger, which is especially true if the family pet is a possible trigger.

Skin testing is required if the patient is interested in allergen immunotherapy.

Rhinoscopy

Rhinoscopy is helpful in direct examination of the upper airway in identifying whether the etiology of rhinitis is obstructive or infectious and for evaluation of nasal polyposis.

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