Here’s a landmark case from the Philosophical Transactions, reported by the Plymouth surgeon James Yonge in 1709:
A girl 16 years old, a daughter of Elizabeth Worth of this town, had about the end of last April a few hot pimples rise on her cheeks, which bleeding and a purge or two cur’d. She continued very well till about a month afterward, when her face, so far as is usually covered with a Vizard-Mask, suddenly turned black like that of a negro.
Vizard masks, rarely used by 1709 but quite common in the sixteenth and seventeenth centuries, were worn outdoors by women of status to prevent sunburn, and to keep their skin fashionably pale.
This surprizing accident much amaz’d and frighted the girl: especially after some foolish people persuaded her she was bewitch’d, and never to be cur’d: by prayers, exorcisms and other incantations they endeavoured to relieve and take off the fascination; which proving ineffectual, the passion and terror of mind increased to a great degree, even to distraction, and then they demanded my assistance.
From what follows, it sounds as if these superstitious (or malicious) neighbours had a serious effect on the poor girl’s mental health.
By the arguments which I used, and some composing anti-hysterical remedies, the violence of her fits became much pacified. I directed a lotion for her face, which took off the discoloration; yet it return’d frequently, but with no regularity, sometimes twice or thrice in 24 hours, sometimes five or six times. It appears insensibly, without pain, sickness, or any symptoms of its approach, except a little warm flushing just before it appears.
Up to this point, the case sounds like one of an abnormal skin pigmentation of some kind; but the truth seems to have been more interesting.
It [the coloration] easily comes away, and leaves the skin clear and white, but smuts the cloth that wipes it from the face; it feels unctuous, and seems like grease and soot, or blacking mix’d: it has no taste at all. She never had the Menses; is thin, but healthful: The blackness appears nowhere but in the prominent part of her face. There are a thousand eye-witnesses to the truth of this uncommon case.
So it was not her skin that had changed colour: some dark substance was being secreted through her pores. If this liquid was removed, her complexion returned to normal.
This makes a tentative diagnosis possible: she may well have been suffering from chromhidrosis, a condition characterised by coloured sweat. The unusual tint of the perspiration is caused by the presence of lipofuscin, a yellow-brown pigment found in many cells. In patients with chromhidrosis, this pigment is oxidised and can appear green, blue, orange or black according to the degree of oxidation. This is the earliest case recorded in the English-language medical literature.
The condition is chronic, and in the early 18th century there was as yet no effective method of treating a condition which was poorly understood. This girl was lucky: it seems to have cleared up on its own.
The anomalous blackness of the girl’s face is now [Nov. 1] divided into a few dark cloudy specks; which appear but seldom, and nothing so livid as formerly.