Another study has added to the growing body of evidence that endocrine-disrupting chemicals can cause direct, measurable harm to the human body. Samsung Medical Center announced on July 8 that exposure to these hazardous environmental chemicals during pregnancy and the immediate postpartum period significantly increases the likelihood that newborns will develop atopic dermatitis, commonly known as eczema.
Endocrine disruptors are external chemical substances that interfere with the body's natural hormone regulation. Common examples include dioxins, harmful byproducts generated primarily during waste incineration; phthalates, which are chemical agents used to soften plastics; and bisphenol A (BPA), widely utilized in manufacturing plastic consumer goods and the protective inner coatings of aluminum cans.
Some critics argue that typical, everyday exposure to these chemicals is too low to clearly impact human health. Because potential endocrine disruptors are found in almost all modern consumer products and are virtually impossible to entirely avoid, skeptics often suggest that public concern is overblown. Nevertheless, substantial scientific evidence links endocrine disruptors directly to chronic disease. The World Health Organization (WHO) has already identified conditions such as declining sperm counts, infertility, and endometriosis as illnesses directly tied to endocrine-disruptor exposure. More recently, clinical research has demonstrated that these chemicals can undermine the human immune system, potentially triggering severe inflammatory diseases or even cancer.
Tracing Eczema Back to Early Chemical Exposure
In this latest breakthrough, a joint research team from the Department of Pediatrics at Samsung Medical Center and National Jewish Health in the United States analyzed the precise relationship between concentrations of phthalate metabolites in newborn urine and the subsequent development of atopic dermatitis. Phthalates are widely used to make plastics flexible in toys, food packaging, and a range of household items, and are known to disrupt the hormonal system when they enter the body through ingestion, inhalation, or skin contact.
When a pregnant woman is exposed to phthalates, the chemicals can cross the placental barrier, directly reaching the fetus. These chemical components can also seep into the amniotic fluid that cushions the developing baby, leading to continuous fetal exposure during critical windows of embryonic skin development.
The research team closely tracked 61 newborns born across four South Korean hospitals between December 2020 and June 2022 for a full year. By the end of the 12-month monitoring period, 11 of the 61 infants had received an official diagnosis of atopic dermatitis.
The decisive differentiator among the infants was their level of exposure to endocrine disruptors. When the team analyzed the newborns' urine 48 hours after birth, infants whose concentrations of broken-down phthalate metabolites met or exceeded the reference threshold of 12.18 μg/L faced an 8.31-fold higher association with an atopic dermatitis diagnosis.
The researchers concluded that this early chemical exposure directly triggers severe inflammatory responses and compromises the skin barrier. When skin cells were exposed to a phthalate solution at levels mimicking typical daily human exposure, cytokines—the immune proteins associated with inflammation—surged. Conversely, key structural proteins essential for maintaining a healthy skin barrier dropped to just one-third of their normal levels. Parallel experiments utilizing artificial laboratory skin yielded identical results, showing sharp declines in skin moisture and a severely weakened barrier function.
“Exposure to endocrine-disrupting chemicals during the earliest stages of life can have a profound impact on infant skin health,” said Professor Kim Ji-hyun of the Department of Pediatrics at Samsung Medical Center, who served as the corresponding author of the study. “This is a critical developmental window where both the skin barrier and the immune system are forming, highlighting the urgent need to carefully evaluate and manage our everyday living environments.”
