Far Beyond the IgE: Insights into the Clinical Profile of Allergic Patients with Selective IgE Deficiency, Urticarial Vasculitis, Allergic Pharyngitis, and Perennial Allergic Conjunctivitis

Aims: Medical literature defines the diagnosis of “selective IgE deficiency” (sIgEd) as the individuals able to produce, at normal amounts, all antibodies’ classes, and subclasses, with exception of the IgE, which is not found by the laboratory detection method (usually below 2.0 kIU/L). Patients with sIgEd may present non—IgE-mediated allergies/hypersensitivities, turning them into ideal subjects to study these conditions.

Study Design: To evaluate by a retrospective chart review the allergic conditions of the sIgEd cohort population attended at an Allergy and Immunology medical facility.

Place and Duration of Study: Instituto Alergoimuno de Americana - São Paulo – Brazil – between January 2018 and January 2023.

Methodology: A population of 6.584 allergic patients, from which 44 (0,6%) meet the criteria for the diagnosis of SIgEd. The prevalence of the medically diagnosed allergic conditions was compared between the groups with detectable IgE and non-detectable IgE to extrapolate the Relative Risk (RR).

Results: The RR of Urticarial Vasculitis for the individuals with sIgEd was 64.2 in relation to the individuals with detectable IgE. The RR of Allergic Pharyngitis for the individuals with sIgEd was 2.65 in relation to the individuals with detectable IgE. The RR of Perennial Allergic Conjunctivitis for the individuals with sIgEd was 2.14 in relation to the individuals with detectable IgE.

Conclusion: The comparison of the prevalence of allergic diseases among two cohorts with detectable and undetectable IgE showed a great tendency for Urticarial Vasculitis and a moderate tendency to develop Allergic Pharyngitis and Perennial Allergic Conjunctivitis among the sIgEd population.