Altered brain connectivity in sensory and motor cortices underlying atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by persistent itching. Growing neuroimaging evidence suggests that chronic itching involves altered brain connectivity within sensorimotor networks. This study aimed to investigate alterations in intrinsic brain connectivity in patients with AD compared to healthy controls, and to assess their association with symptom severity using resting-state functional magnetic resonance imaging (fMRI).

We defined several regions in sensorimotor and other relevant networks as seeds and compared seed-to-whole-brain resting-state functional connectivity (FC) between 41 patients and 40 healthy controls. Correlations between symptom severity and patients' FC were examined.

Patients with AD exhibited decreased FC between the right primary somatosensory cortex (S1) and regions within the default mode network (DMN), and increased FC between the right primary motor cortex (M1) and regions associated with motor execution, reward processing, and emotional regulation. Significant correlations with symptom severity were observed in the FC of the right S1 and supplementary motor areas. Furthermore, differential association patterns were observed in the right S1 and right M1 regarding FC with regions in the DMN.

Our findings revealed altered connectivity in sensory and motor-related regions in patients with AD, reflecting disrupted neural integration of persistent chronic itch. These findings highlight the central neural mechanisms contributing to the chronic itch-scratch cycle and suggest potential clinical applications of neural markers for evaluating disease severity.