Food allergies are associated with various abnormalities in seemingly-healthy skin in pediatric patients suffering from atopic dermatitis (AD). AD is a common skin disorder also known as eczema that makes the skin turn red and itchy. It is long lasting which tends to flare up periodically.
The surprising findings represent one of the most comprehensive skin-related assessments of AD patients to date, and hint that treatments for AD and food allergy should focus on improving the function of the skin barrier.
‘The skin samples of pediatric patients with AD showed decreased levels of filaggrin (skin-associated protein), increased immune response and overgrowth of S. aureus bacteria.’
Atopic dermatitis is an inflammatory skin disorder that affects nearly 20% of children worldwide, and one-third of AD patients also have food and respiratory allergies. Scientists have sought to better understand the relationship between AD and food allergy, but progress has been limited because skin sampling methods such as biopsies are overly invasive.
Here, Donald Leung and colleagues used a noninvasive sampling approach named skin tape stripping to study the skin of 21 patients with AD and food allergy (FA+), 19 patients with AD and no food allergy (FA-) and 22 healthy controls. Their analysis revealed that nonlesional skin from the AD FA+ patients had unique properties not seen in the AD FA- patients. Specifically, the AD FA+ skin samples showed decreased amounts of a skin-associated protein named filaggrin, elevated type 2 immune responses (a form of immune activity mediated by T helper cells) and increased expression of the skin-associated protein keratin - abnormalities that correlated with structural changes in skin barrier architecture. Nonlesional AD-FA+ skin also harbored a higher amount of the bacterial species Staphylococcus aureus compared to AD FA- patients and controls.
Future studies should further examine the complex relationships between S. aureus overgrowth, reduced filaggrin and food allergy sensitization in patients, the authors say.