We consider this fibre-optic instrument a potentially important tool in skin research for non-invasive optical biopsy of primarily the epidermis. Present use is focussed on research applications, where the fluorophore distribution in the skin may illustrate morphological changes in the epidermis.

Dermal pigments from tattoos can be imaged in vivo using CLSM. This application of CLSM has an important future potential for pre-evaluation of tattoos before laser removal, predicting good or poor outcome of laser removal.

This preliminary study demonstrated the applicability of fluorescence CLSM for a detailed study of experimental skin irritants in vivo. Essential findings were disturbed and widened cell borders, swelling of keratinocytes by PA and induction of a parakeratotic shift by SLS with clusters of keratinocytes holding nuclei in the epidermis. Fluorescence CLSM offers a unique opportunity to study the inter- and intracellular water compartments directly in the epidermis in situ and an opportunity to visualize cell proliferation manifested as parakeratosis. Fibre-optic fluorescence CLSM of irritant reactions is, however, technically more complicated than reflectance CLSM and may not be applicable to any irritant. SLS applied epicutaneously interacted with the skin surface and coupling to the microscope and was thus found to be more difficult to study technically than PA. PA dissolved in isopropanol is for technical reasons, and with SLS as alternative, considered the preferred model irritant.

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.

Various non-invasive tools for evaluation of the skin in its natural state were recently introduced. Reflectance confocal laser microscopy (RCM) in vivo can be used in studies of epidermal cells in various inflammatory skin diseases. 1-5 Atopic skin has been studied by RCM. 5 We have applied another mode of confocal microscopy namely fluorescent fibre-optic confocal imaging (FOCI), enabling visualization of the epidermis and outer dermis at higher cellular resolution, for example, at 1000× magnification. 6 Atopic eczema (AE) is a common skin disease in children dominated by eczema, inflammation, and itch. 7 Adults also may suffer from AD. In recent years, the focus has been on epidermal barrier dysfunction measured by increased trans-epidermal water loss (TEWL). 8 The pathology includes increased desquamation, loss of corneocyte cohesiveness, and extracellular lipid contents, thus, changes which might be imaged by FOCI.