Correlation of tear film-specific immunoglobulin E assay with the skin prick test in allergic conjunctivitis

Abstract

Purpose The aim of this study was to investigate the correlation and validity of tear film allergen-specific immunoglobulin E (IgE) in relation to the skin prick test in diagnosing different types of allergic conjunctivitis. Design The study design was a prospective randomized case series. Patients and methods One hundred and twenty patients with allergic conjunctivitis were included in this study and were classified into four groups according to the type of allergy. Group 1 included 48 patients with perennial allergic conjunctivitis. Group 2 included 35 patients with seasonal allergic conjunctivitis. Group 3 included 30 patients with vernal keratoconjunctivitis (VKC), and group 4 included seven patients with atopic keratoconjunctivitis. All patients were subjected to the skin prick test, which was performed with aeroallergen panel using kits containing different inhalant allergens, positive control (histamine 1 mg/ml), and negative control (saline 0.9%). Tear samples were collected using the microcapillary method for the quantitative determination of specific IgE using immune blot assay. Data were evaluated and statistically analyzed. Results In this study, the skin prick test and specific IgE were performed to 11 different allergens and the results revealed that the most common mixed allergens were mixed pollen, mixed mould, and mixed mite. Validity of tear film-specific IgE in the detection of allergens was assessed against the skin prick test (gold standard). There was IgE specificity of 100%, whereas the sensitivity ranged from 50 to 100% to the three common allergens in the four groups. There was a statistically significant correlation between specific IgE and the skin prick test for the most common allergens in patients with perennial allergic conjunctivitis, seasonal allergic conjunctivitis, and VKC (except for mould allergens in the VKC group). There was only a statistically significant correlation between specific IgE and the skin prick test for mite allergen in patients with atopic keratoconjunctivitis. Conclusion Tear film-specific IgE has a statistically significant correlation and validity when compared with the skin prick test in diagnosing the causative allergen in different types of allergic conjunctivitis. It could be a good alternative to the skin prick test in the diagnosis of allergic conjunctivitis with high sensitivity and specificity and fewer complications and limitations.