Investigation of hair shaft in seborrheic dermatitis using atomic force microscopy.

Background/purpose: We have investigated the changes of seborrheic dermatitis (SD) on the hair shaft in the morphological and physical properties using atomic force microscopy (AFM).

Methods: Hair samples were obtained from the lesional and perilesional regions in 15 patients with SD. Fifteen healthy adults were included as the control group. From the topography of hair obtained by AFM, the height of the scale, step height, roughness, diameter, and pit were determined.

Results: The scale thickness of the SD-affected hair was sevenfold more than in the control hair showing statistically significance. The lesional hair showed greater roughness parameters of Sa, Sq, and Sz than the perilesional and the control hair, but this difference was not significant. The cuticle of the lesional hair was significantly damaged while perilesional hair showed a very distinct cuticle structure with smooth edges and a regular interval between the cuticles. The diameter of the lesional hair was significantly lesser by 10-35% than that of the perilesional hair. The pit was rarely observed in the SD-affected hair collected from both the lesional and perilesional regions.

Conclusion: The changes in the hair shaft affected SD was measured using AFM non-invasively. AFM could be a useful tool in monitoring the treatment response and the severity of SD.