Paediatric pain and malnutrition in low-income countries: A narrative review.

Background: Despite its omnipresence, paediatric pain remains poorly understood and documented, especially in low-income countries. Such pain can be a symptom of long-term subclinical conditions such as systemic chronic inflammation (SCI). The latter can be related to malnutrition. Aim: To explore a potential association between paediatric pain and malnutrition in low-income countries. Methods: Narrative review, including a literature search in the PubMed, EMBASE, Web of Science and Scopus databases (update 24 March 2025). The search query comprised controlled terminology and free text words relating to 'Malnutrition', 'Pain', 'SCI' and 'Paediatric'. Results: To comprehend the complex relation between malnutrition and paediatric pain, associations between (1a) malnutrition, and nociceptive brain development, (1b) malnutrition, the gut microbiome and SCI, and (2) SCI and pain were explored. (1a) Early noxious exposure (e.g. malnutrition-related SCI) can cause long-term alterations in pain perception, brain function and structures. The consequences of malnutrition on the nociceptive brain depend on the life-cycle. (1b) Moderate acute malnutrition causes chronic inflammation and exaggerated inflammatory responses. Such responses could indicate hyper-inflammatory phenotypes. (2) Systemic-induced inflammation causes a widespread increase in musculoskeletal pain sensitivity. Conclusion: Malnutrition could contribute to the development of a nociceptive brain and SCI. Malnutrition-related SCI could induce changes in pain perception/thresholds, and predispose to developing chronic pain. If a relation between malnutrition and SCI predisposes children to develop pain, the prevailing biophysical approach needs revision. A multidimensional interdisciplinary approach seems more relevant. Such approach includes social, cognitive, socioeconomic, lifestyle, nutritional (e.g. integrating nutritional and microbiome-targeted interventions) and environmental dimensions.