Severe itching and redness can appear on the face, neck or abdomen. Eczema, also called atopic dermatitis (DA), can severely disturb the quality of life and sleep of infants. These manifestations are frequently developed in wet areas subjected to regular friction, such as the folds of elbows and knees. deep of this affection are still largely overlooked. Nature August 27, 2025 revealed an unsuspected mechanism, directly connecting the child’s health to the experience lived by his mother during pregnancy.
When maternal stress leaves traces on the skin
Several studies had already linked significant stress during pregnancy and the occurrence of an eczema in infants without the cause and effect link having previously been demonstrated. To reproduce stress conditions, researchers have exposed pregnant mice to unpleasant lights, causing an immediate elevation of cortisol, stress hormone.
After birth, their young presented an altered skin barrier, promoting the appearance of eczema. Frucks simulating those of layers or friction in the folds of the elbow and knees were enough to trigger rastered rashes and hypersensitivity, a sign of deep eczematous lesions, while the epidermis of witness mice remained intact and smooth. “”At first glance, no abnormal sign was visible in descendants, apart from a slight alteration of the skin barrier: an increased loss of transepidermal water-that is to say an evaporation of water through the skin greater than usual. However, this condition is known to promote the appearance of eczema, especially in children“Explains Nicolas Gaudenzio.
Hypersensitive neurons and inflammed skin
“”This is the first time that there has been a clear demonstration that infant eczema could have causes prior to the baby’s birth“, Underlines Nicolas Gaudenzio. By continuing their investigation, the researchers used analyzes which revealed a hyperactivation of sensory skin neurons.”This demonstrates nervous hypersensitivity at the skin level, because it is these specialized neurons that transmit the feeling of touch in the form of electrical signals in the brain “specifies Nadine Serhan. In parallel, mastocytes – key immune cells of eczema – were already activated in the absence of stimulus, releasing histamine and predisposing the skin to inflammation. “”In normal times, these immune cells release histamine, the substance at the origin of redness and itching, in the presence of an allergen or irritating agent. But here, mastocytes are already activated at rest, in a neutral environment, which means that the skin is predisposed to develop inflammation“, Details Nicolas Gaudenzio.
Observations in humans who confirm the track
Beyond animal experiences, blood samples conducted from 58 pregnant women in Singapore showed higher cortisol levels in the second trimester in those with eczema (this period corresponds to the moment when immune and nervous systems develop in the skin in humans). This correlation strengthens the idea that prenatal stress could influence the child’s immune and nervous development.
“”These results underline the importance of studying how the experience of pregnant women affects children’s health“Concludes Nicolas Gaudenzio. Researchers now want to continue studies on immune and nervous systems in utero, especially during the second trimester of pregnancy.