D2.51 - ‘Allergy Testing’- but why do we need it? A conceptual misunderstanding leading to diagnostic delay and wastage of health care resources in children referred for 'allergy testing' with poorly controlled eczema

The ‘allergy test’ is only a diagnostic tool to support the clinical diagnosis of allergy; random referral for ‘allergy testing’ without appropriate clinical history in children with poorly controlled eczema is counter-productive and confusing.

A prospective observational study of the referral letter to allergy services for 'allergy test' over 6 months

A total of 60 cases were referred to allergy services for ‘allergy testing’ without a structured clinical history or a pre-referral explanation of 'test' to the caregivers. 70% of patients have poorly controlled eczema, and 80% of these children did not receive steroid cream and were treated with emollients alone. The commonest reason for non-adherence to steroid cream (when prescribed) was parental perception of the side effects of steroid cream, leading to suboptimal management. The commonest pattern of food-induced exacerbation of eczema was urticarial rash (80%) and angioedema (30%). Parents perceived the facial and lip swelling to be the most alarming symptoms. None of these cases had any gastrointestinal or respiratory symptoms. The pre-referral discussion with parents did not focus on the difference between IgE and non-IgE mediated allergy based on clinical history. 70% of cases had pre-referral food allergen-specific IgE tests of random foods; 50% additionally had component-resolved diagnostic tests without a diagnostic yield. The test results were either not explained or misinterpreted before requesting an allergy referral. All these cases also had high IgE levels and active eczema, making it challenging to interpret allergen-specific antibody tests. 30% of cases received adrenaline auto-injectors even before referral to allergy services.

The study highlights a poor understanding of the pathophysiology of allergy, suboptimal pre-referral eczema management, an inability to take a structured allergy history alongside a knowledge gap in defining the non-usability of random ‘allergy testing’. Substantial avoidable wastage of healthcare resources, such as random food allergen specific antibody test and component-resolved diagnostic tests without clinical history are main findings of this study, such unplanned diagnostic tests could add to confusion about future management and unnecessary food avoidance. The basic universal allergy training package may help to improve the knowledge-gap and quality of eczema care through appropriate referral.