Imaging skin: past, present and future perspectives

Skin imaging modalities relevant to the range of skin conditions encountered in clinical settings are described with respect to the information provided, advantages and limitations, current status and indications for further development. The methods use the interaction of energy with the skin, penetrating to various depths in the stratum corneum, epidermis, dermis and subcutaneous layers. They include a detection system such as the retina, film or a digital array, and a processing system to deconstruct, analyze and interpret the information. Similarly, the areas of interest, or targets, have common features. The skin conditions deviate from the ideal or normal state with respect to skin integrity and function. The deviations include evidence of barrier disruption, inflammation, dispigmentation, and vascular change. The user of skin imaging is often interested in the extent and severity of disease. Part of the task in skin imaging is to establish the criteria for the normal condition. The review encompasses the past, present and future of visual assessment, photographic image collection, spectrophotometric techniques, noninvasive histology, and three dimensional scanning. The analytical techniques for processing and extracting specific parameters that inform about the underlying biological status are presented.