TRANS-FOODS study protocol: an observer-blinded, randomized controlled study to assess transcutaneous sensitization to peanut protein in adults with and without atopic dermatitis

BACKGROUND: The rising prevalence of allergic conditions like atopic dermatitis (AD) and food allergies is complex. The dual allergen exposure hypothesis suggests that allergen exposure through skin, particularly in those with AD, can lead to sensitization. This may be exacerbated by skin massage which can enhance allergen absorption by opening the cutaneous appendages. The TRANS-FOODS project aims to elucidate the mechanisms underlying transcutaneous peanut allergy sensitization and evaluate novel preventative strategies, including alterations in peanut processing and adapting skincare practices. As part of the project, a randomized controlled study at King's College London has been set up to investigate whether skin massage facilitates transcutaneous uptake of peanut allergens, particularly in individuals with AD, and whether a barrier-enhancing cream can mitigate this effect. METHODS: We report the study protocol for a single-site, observer blind randomized controlled trial, where healthy adults and adults with AD (n = 130) will be recruited and randomized, applying a peanut protein-containing extract to their outer forearm twice daily with/without massage and with/without a barrier-enhancing cream for a total of 4 weeks. The primary outcome is the potential detection of inflammatory cytokines in skin interstitial fluid (ISF), using a novel non-invasive ISF suction device. In addition, we will study whether the intervention enables detection of peanut protein components in retrieved skin ISF and results in increased transepidermal water-loss measurements. DISCUSSION: To the best of our knowledge, this study will be the first to use a skin massage intervention with a peanut protein-containing solution and a novel ISF extraction device to understand the effects of massage on the immune system and explore the biological signals associated with food sensitization. PROTOCOL REGISTRATION: The trials are registered on ISRCTN (ISRCTN12492694) and ClinicalTrials.gov (NCT05407012).