Title: Trial of IGe tests for Eczema Relief (TIGER): randomised controlled trial of test-guided dietary advice for children with eczema, with internal pilot and nested economic and process evaluations
Funder: Department of Health and Social Care

Abstract: Childhood eczema is common, and many parents/carers worry that a food allergy is the underlying cause. Both eczema and food allergy usually start in infancy when foods are introduced for the first time, strengthening the association in many parents' minds. While allergy may not be the cause of most children’s symptoms, it can be difficult to work out if any given food is causing problems._x000D_ _x000D_ Parents often ask doctors about food allergy tests. Whether a child gets a test depends on who they see. Most GPs do not have access to allergy tests, so refer to a specialist. Wait times on the NHS to see specialists are long and use of allergy tests varies between them._x000D_ _x000D_ If parent’s concerns are not taken seriously, they may be reluctant to use prescribed creams and ointments which they think, “treat the symptoms, not the cause” of eczema. Up to 70% of parents restrict their child’s diet, usually without professional advice, even in mild disease. A limited diet may lead to problems with the child’s growth and health, feeding difficulties and even increase the risk of them developing a food allergy._x000D_ _x000D_ A previous trial suggested that infants with eczema who had a positive allergy test for egg benefitted from an egg-free diet, but a better-designed study is needed. We have shown it is feasible to do a trial in primary care to answer the question “Does dietary advice based on food allergy tests improve disease control in children with eczema?”_x000D_ _x000D_ We will recruit 493 children <2 years of age with eczema from GP surgeries in three areas of England. They will be randomised to two groups: “usual care” or “test guided dietary advice”. Children in the testing group will have skin prick tests, which involves “pricking” small drops of common allergy-causing foods (milk, egg, wheat, and soya) into the skin and noting any local reaction (swelling). Depending on what the tests show, parents will be advised to exclude or include one or more foods for 1 month. Children with unclear results will be observed eating the food at their local allergy clinic first._x000D_ _x000D_ Our main outcome is parent-reported eczema control (the “RECAP” scale) over 6 months. We will ask parents to complete questionnaires every month for 9 months. We will also measure children’s quality of life, dietary variety, and growth. To assess value-for-money, we will collect health and care costs. It is also a unique opportunity to obtain genetic saliva (spit) samples. Making changes to children’s diets based on test results is complex, so we will do a “process evaluation” to assess how things work. This will involve observing the research in action and talking with some participants._x000D_ _x000D_ Families with eczema and clinicians agree that this is a research priority. We have done lots of work with parents of children with eczema/food allergies, which has helped us decide our research question, which foods to test, how dietary advice should be given and what information we should collect. By involving parents in different ways in the running and reporting of the study, we will ensure our research is relevant to the care of children with eczema.

Lay abstract: BACKGROUND: Parents commonly seek food allergy tests or restrict diets, to find a cause for their child’s eczema, yet the value of test-guided dietary advice is uncertain._x000D_ _x000D_ RESEARCH QUESTION: Does dietary advice based on routine food allergy tests improve disease control compared with usual care in children with eczema?_x000D_ _x000D_ DESIGN: Pragmatic, multi-centre, parallel group, individually randomised controlled trial (RCT), with internal pilot and nested economic and process evaluation._x000D_ _x000D_ SETTING: Primary care (84 GP surgeries)._x000D_ _x000D_ PARTICIPANTS: Children (<2 years) with eczema._x000D_ _x000D_ INCLUSION: Eczema, mild or worse._x000D_ _x000D_ EXCLUSION: Previous SPT/IgE blood test for, or confirmed IgE-mediated food allergy to, study foods._x000D_ _x000D_ INTERVENTION: “Good eczema care” leaflet plus dietary advice based on skin prick tests to milk, egg, wheat, and soya, delivered by trained research/practice nurses._x000D_ _x000D_ COMPARATOR: “Good eczema care” leaflet, to standardise treatment. _x000D_ _x000D_ ALLOCATION: Randomised to intervention or comparator groups (1:1 ratio), stratified by eczema severity and centre._x000D_ _x000D_ PRIMARY OUTCOME: RECAP (parent completed measures of eczema control) collected four-weekly for 24 weeks. _x000D_ _x000D_ SECONDARY OUTCOMES (over 36 weeks): eczema symptoms (POEM); quality of life (child IDQoL and CHU-9D; parent EQ-5D-5L and Carer QOL); adverse events; dietary variety and primary food groups; weight-for-age and stature-for age; breastfeeding status; parent/carer anxiety (GAD-7)._x000D_ _x000D_ SAMPLE SIZE: 493 children will detect a difference of 1.95 on RECAP between all children in the two treatment groups assuming a standard deviation in RECAP of 6.5, correlation between baseline and 24-weeks of 0.4, 20% loss to follow-up, 90% power and 5% significance level._x000D_ _x000D_ ANALYSIS: The primary analysis will be performed using a multilevel mixed model framework with observations over time (level 1) nested within participants (level 2)._x000D_ _x000D_ ECONOMIC EVALUATION: The primary perspective will be NHS; cost-utility analysis will compare quality-adjusted life years (QALYs) gained for the child and main carer to costs incurred by the NHS. Additionally, costs from NHS and non-NHS perspectives will be related to a range of outcomes in a cost-consequences approach._x000D_ _x000D_ PROCESS EVALUATION: In-depth interviews with ~15 GPs; ~15 Research and Practice Nurses; ~30 parents; observation of nurse training sessions; and audio-recording of baseline and intervention group encounters. Quantitative exploration of potential mediators of adherence and intervention outcomes._x000D_ _x000D_ PATIENT AND PUBLIC INVOLVEMENT: “What role might food allergy tests play in treating eczema?” is a James Lind Alliance research priority. We have surveyed 152 parents, held 6 meetings and 3 public engagement events. We are committed to strong PPI in delivery, with a PPI&E coordinator, co-applicant, TSC member, and advisory group._x000D_ _x000D_ DISSEMINATION: Our established networks will reach beyond traditional outputs, working with professional bodies in allergy, dermatology, primary care and commissioners to help implement the study’s findings. Uptake will be facilitated by the interest in clinical and lay communities about this issue._x000D_ _x000D_ PROJECT TIMETABLE: 40 months duration, including 6 months set-up, 29 months recruitment and follow-up, 5 months analysis and reporting.

Research activity codes: 6.7 PHYSICAL
Health categories: INFLAMMATORY AND IMMUNE SYSTEM;SKIN