“White plague” was a term for tuberculosis that enjoyed some popularity in the late 1800s, at a time when the disease was pandemic in the industrialized world. Specifically, it refers to pulmonary tuberculosis— tuberculosis of the lungs, which was then generally known as consumption or phthisis.
Oliver Wendell Holmes is credited with coining the term in 1867, in a lecture given at Harvard University: “Two diseases especially have attracted attention, above all others, with reference to their causes and prevention; cholera, the 'black death' of the nineteenth century, and consumption, the white plague of the North, both of which have been faithfully studied and reported on by physicians of our own State and city.”1
The ‘plague’ part is pretty self-explanatory, considering the severity and the scope of the disease at the time. During the nineteenth century, tuberculosis killed more people in the developed world than any other disease, with mortality rates generally running around 300 per 100,000.2 Where the ‘white’ comes from is a little harder to discern. It may refer to the paleness of the sickly tubercular, who often suffered from anemia. Another possibility is hinted at by Holmes’ phrasing: he calls cholera the “‘black death’ of the nineteenth century,” highlighting the similarity between it and plague, which both tended to spread across Europe in periodic epidemics before disappearing for years. Calling tuberculosis the ‘white plague’ may just be a way of contrasting it with such diseases, since tuberculosis, rather than coming and going in great bursts, seemed to simmer constantly in the population.
1Medical Essays, 1842-1882, p 352.
2Harrison, Mark. Disease and the Modern World. Cambridge: Polity Press, 2004.