Removal of volatile organic compounds by chemical filters significantly inhibited the development of atopic dermatitis symptoms in mice: potential implications for air-conditioning systems in healthcare environments.

Volatile organic compounds (VOCs) are increasingly implicated in systemic diseases, but their contribution to skin disorders such as atopic dermatitis (AD) remains unclear. This study assessed VOC concentrations in medical environments, their effects on AD development, and the efficacy of VOC removal using chemical filters. Total VOC levels were monitored in 3 types of veterinary hospitals. AD-like lesions were induced in female NC/Nga mice by repeated dermal application of toluene diisocyanate or house dust mite ointment, with or without topical exposure to a VOC mixture (10 μg/ml). Clinical parameters, including dermatitis scores, transepidermal water loss, and skin thickness, were measured weekly, and immunological and histological analyses were performed. VOC monitoring revealed that 1 hospital exhibited concentrations exceeding 400 μg/m³. In the mouse model, direct VOC exposure significantly aggravated keratinocyte inflammation and worsened AD symptoms. Application of chemical filtering systems effectively reduced VOC levels in real clinical settings, and their use in the experimental model suppressed AD development. However, therapeutic application of VOC removal showed only limited effects on systemic immunological markers. These findings suggest that VOCs present in healthcare environments may contribute to the onset and progression of AD. Incorporating VOC-removing filters into air-conditioning systems could serve as a preventive strategy to improve the management of allergic skin diseases.