Whether pellagra is or is not to be regarded as one of the deficiency diseases from the point of view of the vitamin hypothesis is still open to question. There is, however, sufficient evidence for the affirmative to warrant its consideration at least.1

The disease is one which has been common for centuries in some parts of Europe, notably in Northern Italy and Roumania. It made its appearance in Southern France in the disastrous period following the reign of Napoleon, but disappeared later, apparently with the betterment of economic conditions, and is now almost unknown there. While there are records of occasional cases in the Southern United States as far back as 1828,la it was little known until about the beginning of the present century. In the course of the last twenty years it has increased rapidly, no fewer than 500,000 cases having been reported within this period. The Metropolitan Life Insurance Company, which operates extensively in the cities and towns of the South, records 2,310 deaths from this disease between 1911 and 1916, a death rate which is higher than that for either malaria or general tuberculosis. In 1916 pellagra ranked fourth as a cause of death in Mississippi, with 840 deaths, third in Alabama, with 677 deaths, and second in South Carolina, with 627 deaths.

At the time of the second Pan American Scientific Congress it was said to be practically unknown in Central and South America, but Roberts has recently stated that it is now found in Mexico, Yucatan, Panama, and the Hawaiian Islands, as well as in every state in the Union.

1 Babes (Bull. soc. sci. acad. Roumaine 6, 138, 1920) considers that recent researches have not been of a nature to clarify either the etiology or the pathogenesis of pellagra. He thinks they have only increased the uncertainty by new hypotheses, by misinterpretation of facts, and by poorly executed work which will pass into oblivion. The following facts concerning pellagra he avers have been established: (1) The close relationship of the disease with the eating of maize, especially unwholesome maize. (2) The predisposition produced in inanition, weakness, congenital deterioration especially of a nervous type, certain diseases, and convalescence from these diseases. (3) The specific nature of pellagra. (4) The favorable action of an abundant mixed diet and the administration of atoxyl.

1a Goldberger, Proc. 2nd, Pan. Am. Sci. Cong. 1917, Section 8, Pt. 2, p. 20.

It is very commonly asserted that pellagra attacks the white race more frequently than the negroes, but while this is true in certain sections of the country, in others the reverse holds. In Charleston, S. C. there are said to be three cases among the colored population to every one among the whites, while in Alabama the disease is evenly distributed among the negroes and the whites.2

It has very rarely been observed in children under the age of one year, but is not so rare in the second year and fairly common between two and twelve years. The period from twelve to sixteen years is relatively free from initial attacks of pellagra, but after sixteen, pellagra incidence rises rapidly in women, the rise being especially sharp in colored women. It is very much more common among women than among men. In a group of 414 cases between the ages of 20 and 44 coming under the observation of the Thompson Pellagra Commission there were 357 women as against 57 men.8 Between the ages of 20 and 50 years, however, the number of women attacked gradually diminishes and the number of men gradually increases, so that the two sexes are approximately equal in this respect at 50. In old age the onset of pellagra is slightly more common in men than in women.

The disease is a periodic one, appearing in the spring and early summer and disappearing again as colder weather sets in. The symptoms are described by Goldberger4 as follows:

In a fairly well developed though not advanced case the disease shows itself by a variety of symptoms, of which weakness, nervousness, indigestion, and an eruption form the most distinctive combination. The eruption is the most characteristic telltale of the disease and the main reliance in its recognition. When the eruption first shows itself it may look very much like a sunburn, the deceptive resemblance to which may, in some cases, be heightened by the subsequent peeling with or without the formation of blisters. In many cases the infiamed-looking skin first turns to a somewhat dirty brown, frequently parchment-like, then quickly becomes rough and scaly, or cracks and peels. In many instances, however, the beginning redness is not noticed or does not occur, the first and perhaps the only thing observed being the dirty-looking scaly patch of skin very much like and frequently thought to be no more than a simple weathering or chapping.

Among the most distinctive peculiarities of the eruption is its preference for certain parts of the body surface. The backs of the hands in adults and the backs of the feet in children are its favorite sites. Other parts not infrequently attacked are the sides or front of the neck or both, the face, elbows, and knees.

2 Slier, Proc. 2nd Pan. Am. Sci. Cong. Sect. 8, Pt 2. p. 14.

3 Siler, lb.

4 Goldberger, Pub. Health Repts. 88,481,1918.

From these or other points, for it may attack any part of the body it may spread to a varying degree. Another marked peculiarity of the eruption is its tendency to appear at about the same time, and to cover similar areas, both as to extent and peculiarities of outline, on both sides of the body. Thus it may be stated as the rule that if the back of one hand or of one foot, one elbow, one knee, one side of the neck, one cheek, or the lid of one eye is affected, then the corresponding part on the other side of the body is affected, and affected to almost exactly the same extent. This rule, however, is not without many exceptions. It must not be assumed, because the back of one hand or of one foot or of one side of the neck alone seems to be involved, or is involved to so slight an extent as to be almost nothing in comparison with the involvement of the other side, that the possibility of the disease being pellagra may be thrown out of court without further ado.