The First Glance

The story of dermoscopy begins not in a dermatology clinic, but in the study of a seventeenth-century French polymath. Pierre Borel (c. 1620–1671) — physician, botanist, and alchemist — was the first person known to have turned a microscope on living human skin.

In publications from 1655 and 1656, Borel described using a microscope to observe the tiny blood vessels of the nail bed. Eight years later, in 1663, Johan Christophorus Kolhaus reproduced these observations.

It would be misleading to call this dermoscopy in any modern sense. Borel and Kolhaus were not diagnosing disease — they were doing something more fundamental. William Harvey had published De Motu Cordis in 1628, but his theory of blood circulation had not yet been confirmed at the capillary level. Malpighi's direct observation of capillaries would not come until 1661. In this context, Borel's nail-bed observations were physiological evidence, not clinical practice. What he demonstrated was a principle: that magnification could reveal structures in living skin invisible to the naked eye. It would take centuries for anyone to think of using that principle diagnostically.