Trial of food allergy IgE tests for Eczema Relief (TIGER): study protocol

Food allergy may contribute to eczema, but there is variability in the use of tests to investigate this, and uncertainty about possible benefits or harms. The objective is to determine the clinical and cost-effectiveness of test-guided dietary advice compared with standard care for eczema management.

This is a pragmatic, multicentre, parallel group, individually randomized controlled trial with internal pilot and nested genetic substudy and economic and process evaluations. Children (aged 3 months to <2 years) were recruited via general practitioner surgeries in England and randomized 1:1 to standard care or intervention. Both groups received a 'Good eczema care' leaflet. The intervention group also received dietary advice for cow's milk, hen's eggs, wheat and soya, based on skin prick tests and dietary history.

The primary outcome is parent-reported eczema control [RECap for AtoPic eczema (RECAP)], completed 4-weekly over 24 weeks. Secondary outcomes include eczema symptoms; quality of life; adverse events; breastfeeding status and diet; growth; and parental anxiety. The primary analysis is a multilevel mixed model framework with observations over time nested within participants. A cost-utility analysis will compare quality-adjusted life years for the child and main carer to costs incurred by the National Health Service (NHS) between groups. Additionally, costs from NHS and non-NHS perspectives will be related to a range of outcomes in a cost-consequences approach. A nested process evaluation will assess intervention fidelity, clarify causal mechanisms and identify contextual factors associated with variation in outcomes. This trial will fill an evidence gap of clinical importance and reduce variation in practice and associated harms.

The protocol is registred with ISRCTN (ISRCTN52892540): https://www.isrctn.com/ISRCTN52892540.