‘My complexion is black and white and every wrong colour,’ an exasperated Jane Austen wrote in her diary. ‘I am more and more convinced that bile is at the bottom of all I have suffered.’

The famous author was describing the dermal particulars of a disease that had afflicted her for two years – and would eventually take her life. Although unknown to medicine at the time, Austen was suffering from Addison's disease, the same syndrome that more than a century later, would afflict John F. Kennedy. Austen thought she was plagued with ill humors, specifically bad bile, a general pathological idea that muddied much of Western medicine in those days. It wasn't until 150 years later, in 1964, that the truth came out. A physician writing in the British Medical Journal made the correct diagnosis by poring over some of the remarkably detailed descriptions in her diary.

The physician found a perfect summary of Addison's symptoms, an insidious and progressive deterioration of the adrenal cortex. These organs, which secrete a variety of important hormones, sit on the roof of your kidneys in the same manner that snow sits on a mountain top. Their atrophy leads to a severe drop in blood pressure, to weight loss and an overall feeling of weakness. If left unchecked (it is usually treated with steroids), Addison's also causes an overproduction of the skin pigment melanin. This pigment causes the skin to darken considerably, producing an uneven, blotchy black/brown/white complexion all over the body.