Blue Light Phototherapy May Cause Short-Term Skin and Gut Changes in Newborns, Finds Study
USA: Blue light phototherapy used to treat neonatal hyperbilirubinemia may cause temporary increases in transepidermal water loss, skin changes, alterations in the gut microbiome, and inflammatory signaling. Although no long-term effects have been identified, researchers recommend further studies to better understand the potential clinical significance of these short-term changes.
The findings were discussed in a review published in Pediatric Dermatology by Meshi Paz, Tulane University School of Medicine, New Orleans, Louisiana, USA, and Peter Lio, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA. The review examined the relationship between blue light phototherapy (BLP) and the developing neonatal skin barrier, microbiome, and immune system.
Neonatal skin undergoes rapid maturation during the first weeks of life while simultaneously supporting microbial colonization and immune development. Because these processes are interconnected, exposures occurring during this period could potentially influence more than the skin alone.
BLP is widely used and remains an essential treatment for neonatal hyperbilirubinemia. However, emerging evidence suggests that its effects may extend beyond the immediate breakdown of bilirubin. The review highlights findings indicating that phototherapy can influence skin barrier function, microbial communities, and inflammatory and oxidative pathways.
The researchers noted that neonatal skin functions as an active immune organ and communicates with other biological systems, including the gastrointestinal, nervous, and endocrine systems. Changes induced by BLP at the skin level could therefore potentially interact with these pathways. The possible relationship between phototherapy-associated changes and immune-mediated conditions such as atopic dermatitis was also discussed, although the available evidence does not establish a causal association.
Key findings include:
- BLP may temporarily increase transepidermal water loss, suggesting an effect on neonatal skin-barrier function.
- Phototherapy may influence the composition of both cutaneous and gastrointestinal microbial communities.
- Changes in inflammatory and oxidative signaling have been reported following exposure.
- The biological effects of BLP may involve interactions between the developing skin, microbiome, and immune system.
- Current evidence is insufficient to determine whether these short-term changes have lasting clinical consequences.
Interpretation of the available evidence is complicated by substantial differences in phototherapy practices. Studies have used different light sources, wavelengths, irradiance levels, treatment durations, distances, and exposed skin areas. Infant characteristics, including gestational age, birth weight, bilirubin levels, feeding status, and underlying illness, may also influence outcomes.
The authors emphasized that these observations do not currently support changes to standard neonatal phototherapy protocols or routine dermatologic treatment during phototherapy. Instead, they suggest that BLP should be considered a biologically active exposure during a critical period of development. Long-term, well-designed studies that account for treatment parameters and individual infant characteristics are needed to determine whether the observed effects have meaningful clinical implications.
Reference:
Paz, M., & Lio, P. Illuminating Connections: Exploring the Dynamic Relationship Between Phototherapy and the Skin. Pediatric Dermatology. https://doi.org/10.1111/pde.70330
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