Fluorescent fibre-optic confocal imaging of lesional and non-lesional psoriatic skin compared with normal skin in vivo



Christian Suihko

Department of Dermatology

Linköping University Hospital

S-581 85 Linköping


Tel: +46 13 22 25 74

Fax: +46 13 22 25 62

e-mail: christian.suihko@liu.se



Fibre-optic confocal imaging (FOCI) allows non-invasive visualization of live skin in vivo. A contrast agent, a fluorophore, is injected in the dermis. FOCI images are optical sections from a horizontal (en face) view. The aim was to study epidermis and the cellular structure of keratinocytes of psoriatic plaques and adjacent non-lesional with healthy skin as a reference.


Twelve patients with stable plaque psoriasis were studied and compared with a control group of eight healthy individuals. Fluorescein sodium was used as fluorophore. A hand held fibre-optic laser scanner (Stratum®; Optiscan Pty., Melbourne, Australia) was used. The study included morphometric analyses.


The confocal in vivo images demonstrated characteristic features of epidermis and keratinocytes in lesional and non-lesional skin vs. healthy skin. Morphometry based on FOCI demonstrated an approximately 30% increased width of keratinocytes of psoriatic skin vs. healthy control, and the number of keratinocytes per viewing field was reduced. FOCI allowed non-invasive visualization of cell nuclei and parakeratosis of psoriatic epidermis. The horizontal width of dermal papillae of psoriatic skin was increased by approximately 50% as compared with healthy skin, and the flow of erythrocytes in the papillar vessels could be observed in real-time.


FOCI can directly visualize essential epidermal structures of plaque psoriasis in vivo, in real-time and with cellular resolution without the need of taking biopsies and thus without disturbing the natural state of the skin. FOCI is a versatile future tool for non-invasive microscopic diagnosis and therapy follow-up of psoriasis.