Sam Shuster, professor of dermatology at the University of East Anglia, believes the revolutionary thinker had hidradenitis suppurativa (HS) in which the apocrine sweat glands -- found mainly in the armpits and groin -- become blocked and inflamed.
"In addition to reducing his ability to work, which contributed to his depressing poverty, hidradenitis greatly reduced his self-esteem," said Shuster, who published his findings in the British Journal of Dermatology."This explains his self-loathing and alienation, a response reflected by the alienation Marx developed in his writing."
While HS is linked to boil-like lumps, the painful condition also causes more widespread infection, swelling, skin thickening and scarring.
It could also explain a number of Marx's other complaints, not previously linked, such as joint pain and a painful eye condition which often stopped him working.
Shuster based his diagnosis on an analysis of Marx's extensive correspondence, in which he wrote to friends about his health and described his skin lesions as "curs" and "swine."
"The bourgeoisie will remember my carbuncles until their dying day," Marx told Friedrich Engels in a letter from 1867.
Marx, who died in 1883, was one of the most influential philosophers of the 19th century and his radical writings formed the basis of modern communism.