Dermatology has always been a visual field, dependent on visible changes on the skin for correct diagnosis and monitoring of therapy. Before the invention of photography, dermatological disease was painstakingly catalogued with drawings, paintings, and moulages. Photography, especially digital photography, has transformed the way dermatology is practiced by capturing a patient’s dermatological complaint as it is presented and integrating these images into patient care.
As far back as the 1860s, silvered copper plate daguerreotypes and early photographs were found in specialized dermatological publications such as Alexander John Balmanno Squire’s Atlas of the Diseases of the Skin.1 It was therefore natural for dermatology to continually adopt new technologies and techniques in photography and printing as they became available. This allowed for dermatology to flourish as a specialty in which a patient’s disease process could be visually documented in detail along with its histology. The development of the 35 mm Kodachrome (Eastman Kodak Company, Rochester, NY) became the gold standard of clinical dermatologic photography.2 However, film photography was limiting due to its cost and processing time. Despite these limitations, it endured for over a century.
Digital photography is a relatively recent advance in the capture and storage of visual information. As digital photographic technology has advanced and increased in accessibility and cost-effectiveness, dermatologists have been at the forefront of its utilization in patient care. Digital photography has quickly become the standard method for photographic documentation for both clinical applications and publication purposes.3 In addition to replacing film photography in dermatological study and practice, digital photography also offers many advantages. Some of these are straightforward, such as a switch from a film medium with a limited existence under routine storage to a reproducible, immortal digital medium. For example, the archival and quick retrieval of digital images is made significantly simpler and more cost-effective than retrieval of film images as they can be stored and searched on a computer. Beyond these types of advantages, however, are entirely new options that are made possible by digital photography.
With many dermatologic diseases, it is important to know whether a particular lesion is new or recurrent. To accomplish this goal, multiple photographs can be compared over time by documenting the patient’s initial presentation and then obtaining serial photographs over time or at definitive endpoints. In addition, in a process termed image registration, multiple images of the same subject area are aligned and overlaid in a manner that allows one to compare changes over a period of time using both visual and computational methods4 in a manner far simpler than could be accomplished with film. Photography provides a uniquely visual medical record that cannot be obtained by descriptive documentation alone.
There have also been advances in computerized assessment of pigmented lesions and early identification of melanoma. By performing analysis on large numbers of digital photographs of melanoma, software systems are able to “learn” ...