PELLAGRA (Ital. pelle agra, smarting skin), the name given, from one of its early symptoms, to a peculiar disease, of comparatively modern origin. For some time it was supposed to be practically confined to the peasantry in parts of Italy ( particularly Lombardy) and France, and in the Asturias (mal de la rosa), Rumania and Corfu. But it has recently been identified in various outlying parts of the British Empire (Barbadoes, India) and in both Lower and Upper Egypt; also among the Zulus and Basutos. In the United States sporadic cases had been observed up to 1906, but since then numerous cases have been reported. It is in Italy, however, that it has been most prevalent. The malady is essentially chronic in character. The indications usually begin in the spring of the year, declining towards autumn, and recurring with increasing intensity and permanence in the spring seasons following. A peasant who is acquiring the malady feels unfit for work, suffers from headaches, giddiness, singing in the ears, a burning of the skin, especially in the hands and feet, and diarrhoea. At the same time a red rash appears on the skin, of the nature of erysipelas, the red or livid spots being tense and painful, especially where they are directly exposed to the Sun. About July or August of the first season these symptoms disappear, the spots on the skin remaining rough and dry. The spring attack of the year following will probably be more severe and more likely to leave traces behind it; with each successive year the patient becomes more like a mummy, his skin shrivelled and sallow, or even black at certain spots, as in Addison's disease, his angles protruding, his muscles wasted, his movements slow and languid, and his sensibility diminished. Meanwhile there are more special symptoms relating to the nervous system, including drooping of the eyelid, dilatation of the pupil, and other disorders of vision, together with symptoms relating to the digestive system, such as a red and dry tongue, a burning feeling in the mouth, pain on swallowing, and diarrhoea. After a certain stage the disease passes into a profound disorganization of the nervous system; there is a tendency to melancholy, imbecility, and a curious mummified condition of body. After death a general tissue degeneration is observed.
The causation of this obscure disease has recently come up for new investigation in connexion with the new work done in relation to sleeping-sickness and other tropical diseases. So long as it was supposed to be peculiar to the Italian peasantry, it was associated simply with their staple diet, and was regarded as due to the eating of mouldy maize. It was by his views in this regard that Lombroso (q.v.) first made his scientific reputation. But the area of maize consumption is now known to be wider than that of pellagra, and pellagra is found where maize is at least not an ordinary diet. In 1905 Dr L. W. Sambon, at the meeting of the British Medical Association, suggested that pellagra was probably protozoal in origin, and subsequently he announced his belief that the protozoon was communicated by sand-flies, just as sleeping-sickness by the tsetse fly; and this opinion was supported by the favourable action of arsenic in the treatment of the disease. His hypothesis was endorsed by Sir Patrick Manson, and in January 1910 an influential committee was formed, to enable Dr Sambon to pursue his investigations in a pellagrous area.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)