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Wise et al.

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positive response to CPT is simple to evaluate, because it consists of an immediate reaction (from 5 to 20 minutes from the instillation) with ocular itching, tearing, redness, and possibly conjunctival edema. In 1984, a study of 20 children with seasonal rhinoconjunctivitis tested 3 times with CPT reported good reproducibility. 1080 In 2001, a diagnostic sensitivity and specificity of 90% and 100%, respectively, was reported in mite allergic patients. 1081 A very recent systematic review was performed and the results were published in the EAACI guidelines for daily practice of CPT, with grade B evidence for the capacity to individuate the allergen trigger. 1082 The conclusion highlighted that allergists should be more familiar with CPT due to its simplicity. However, the scales to assess the symptoms need to be validated, the standardization of allergen extracts must be improved and the indication to perform CPT in patients with forms of conjunctivitis other than allergic remains uncertain. • Aggregate Grade of Evidence for Nasal Provocation Testing: C (Level 2b: 4 studies). Of note, this evidence grade is based on the studies listed in Table VIII.H.2. However, due to the variation in NPT technique and outcome measures, a reliable evidence grade for NPT is difficult to determine. Nasal cytology (NC) is a simple diagnostic procedure that evaluates the health of the nasal mucosa by recognizing and counting cell types and their morphology. 1087 NC requires 3 steps. The first is sampling the surface cells in the nasal mucosa with an appropriate device via anterior rhinoscopy. The most commonly used collection device is the Rhino-probe (Arlington Scientific, Springville, UT, USA). 1088 The second step is staining by the May Grunwald-Giemsa method, which allows for identification of all inflammatory cells present in the nasal mucosa (ie, neutrophils, eosinophils, lymphocytes, and mast cells) as well as normal mucosal cells (ciliated and mucinous), and even bacteria or fungi. The third step is examination through an optical microscope able to magnify up to 1000×. For the analysis, at least 50 microscopic fields must be read to be sure to detect all the cells in the sample. 1087 NC may detect viruses, fungi, and bacteria (including biofilms) in the nose, allowing for the diagnosis of infectious rhinitis. 1089 Specific cytological patterns on NC can help in discriminating among various forms of rhinitis, including AR, NAR, idiopathic rhinitis, and overlapping forms. AR is commonly diagnosed by the combination of clinical history and results of in vivo and/or in vitro tests for sIgE antibodies. 1090 When assessed by NC, the predominant cell type is the eosinophil, followed by mast cells and basophils. 1091-1094 In a logistic regression model, elevated nasal eosinophil counts on NC has an OR of 1.14 (95% CI, 1.10 to 1.18) to identify AR. 1092 It has been described that NC in polyallergic patients shows a more intense inflammatory infiltrate than in monoallergic patients. 1093 NC has also demonstrated seasonal changes of inflammatory cells in the nose, probably mirroring the variations in allergen exposure, in patients with mite-induced rhinitis. 1095 Negative allergy testing in patients with persistent rhinitis usually suggest a diagnosis of NAR. 1096 The first variant of NAR, known as NARES, was described after the identification of a subset of patients with perennial rhinitis, negative skin tests, and marked eosinophilia in nasal secretions. 174 In more recent years, other variants have been defined, including NAR with mast cells (NARMA), with neutrophils (NARNE), and with eosinophils and mast cells

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VIII.I. Nasal cytology and histology

Int Forum Allergy Rhinol . Author manuscript; available in PMC 2020 June 10.