Allergic Rhinitis in Otolaryngology and Facial Plastic Surgery Workup

The diagnosis of allergic rhinitis is based on the history, and tests are used only to confirm atopy.

Nasal cytologic studies may be needed.

• Nasal secretions are stained with hematoxylin and eosin.
• In general, the presence of eosinophils and goblet cells is suggestive of allergy, whereas the presence of neutrophils and bacteria is characteristic of infection.

An elevated eosinophil count can occur in patients with asthma, nonallergic rhinitis with eosinophilia syndrome (NARES), and parasitic infection. Therefore, this finding is not specific to allergic rhinitis.

Skin tests may be performed.

• Skin testing is generally considered to be the standard of allergy workup. The classic wheal-and-flare responses result from the interaction between the antigen and sensitized mast cells in the skin.
• In general, the acute phase starts within 2-4 minutes and reaches a maximum in 10-20 minutes. It may be followed by a late phase 4-6 hours later. A number of factors affect the responses; these include the following:

  • Volume and potency of the antigen
  • Reactivity of the skin
  • Age and race of the patient
  • Area of body tested
  • Distance between the injections and time of day of testing
  • Medications (eg, antihistamines and tricyclic antidepressants)
• Because of these variables, positive and negative controls must be used to ensure the validity of the results.
• In addition, patients receiving beta-blocker therapy are at risk for severe reactions, and the drugs should be switched to another class of medication before testing is initiated.
• Currently, 3 types of skin tests are in use.

  • Prick testing is rapid and safe, and scores are graded from 0-4 according to both wheal and flare responses. However, low-grade sensitivities can be missed. Therefore, the test is often used as a screening tool, which is followed by intradermal testing if necessary.
  • Single-dilution intradermal testing involves injecting 0.01-0.05 mL of antigen into the epidermis. The resulting wheal and flare are measured after 10-20 minutes and graded as in prick testing. This test can be used to detect most low-degree atopies if a 1:500 concentration is used. However, as with prick testing, it does not permit accurate quantitation of the sensitivity to the antigen involved.
  • Progressive-dilution intradermal testing (skin endpoint titration) involves a series of 5-fold dilutions, starting with a concentration that is sufficiently dilute to be nonreactive. Progressively stronger concentrations are injected until a wheal forms. The endpoint is confirmed when the wheal with the next stronger dilution is 2 mm larger than the previous wheal. This endpoint indicates the relative sensitivity of the patient to the allergen and designates the starting point for immunotherapy. This method allows both qualitative and quantitative assessment of sensitivity to the antigen in question.

The IgE count may be determined.

• In contrast to total IgE, which has a poor clinical correlation, antigen-specific IgE antibodies are important in the diagnosis of inhalant allergy.
• Compared with skin testing, in vitro testing is more specific, and it is not affected by skin reactivity or medications. It also has no risk of systemic reaction and is better tolerated, because it is less traumatic. However, in vitro testing is less sensitive than skin testing, especially in regard to molds. Also, the results are not available immediately and must be verified with skin testing before immunotherapy can be started.
• The original method for obtaining an IgE count, the radioallergosorbent test (RAST), has evolved from a radioimmunoassay to a test that involves enzymatic or fluorometric processes (eg, enzyme-linked immunosorbent assay [ELISA]).

  • Fadal and Nalebuff have modified the test to increase its sensitivity and to improve the correlation of its findings to those obtained with the skin endpoint titration method.
  • Scores do not necessarily correlate with the severity of the clinical symptoms. Although they can be used to establish the starting dose for immunotherapy, a vial test still is required before immunotherapy can be initiated.

• No radiologic studies are necessary in the evaluation of patients with allergies because the diagnosis is made on the basis of the history and confirmed with relevant physical findings and test results.
• Imaging findings, if available for other reasons, are usually nonspecific and may be the same as those in other types of rhinosinusitis (eg, mucosal thickening, turbinate hypertrophy).

• Many other alternative tests for allergies are available, but they have not been fully validated yet.
• These include the following:

  • Basophilic histamine-release test
  • Cytotoxic test
  • Leukocyte antibody test for related antigens