410 THE BIOCHEMISTRY OF B VITAMINS 



which continues until the progressively weakened condition of the pel- 

 lagrin results in death, most often in about five years. Nicotinic acid 

 therapy is highly and rapidly effective for all the symptoms that are 

 clearly due to the niacin deficiency, but since pellagra is a multiple 

 deficiency, complete cure is obtained only by multiple vitamin therapy. 

 In advanced cases where irreversible pathological changes have occurred, 

 of course, vitamin therapy has only limited efficacy. 



The cardinal symptoms of pellagra are often referred to as the three 

 "D's," dermatitis, diarrhea, and dementia. Gastric disturbances, anorexia, 

 headache, and loss of weight and strength are among the earliest symp- 

 toms. Diarrhea may occur quite early, and frequently becomes one of 

 the severest symptoms in later stages. Para-sprue, a condition that is 

 widespread in India and similar in many respects to sprue (p. 417) , is 

 undoubtedly a compound deficiency, principally involving niacin de- 

 ficiency, and distinguishable from true sprue by the nonfatty nature of 

 the stools. 8s In pellagra, redness of the tip and margin of the tongue 89 

 and lining of the mouth, and a characteristic gingivitis and gastric 

 irritation are almost invariable; at the height of the disease the tongue 

 becomes swollen and cracked, and peels and appears cyanotic in many 

 cases. 90 Nausea is frequent, and along with this and the diarrhea, 40 per 

 cent of the cases develop an achlorhydria. The dermatitis is bilaterally 

 symmetrical in most but not all cases, 85 clearly defined, and generally 

 restricted to a necklace or gauntlet pattern about the neck, and to the 

 dorsal surfaces of the hands and forearms, although it may occur on 

 other areas exposed to sunlight (the face and lower legs) and on areas 

 subject to chafing. Frequent characteristic scrotal lesions are also believed 

 to be due to niacin deficiency, although this point seems uncertain. 91 - 92 

 The dermatitis generally originates in the form of deep red areas that 

 gradually become brown and coalesce and later become thickened and 

 scaly. 



Unlike the symptoms in beriberi or ariboflavinosis, there is a high 

 incidence of mental symptoms in pellagra, and these may range from 

 mild psychoneurosis and insomnia to stupor or mania. The existence of 

 acute mental disorders in this case, and their rapid cure by niacin therapy 

 merits special consideration from the standpoint of its bearing upon the 

 nature of mental disease in general. The longstanding and widespread 

 concept of a purely psychological etiology in the insanities has resulted in 

 little general advance in the cure of these diseases. Very recently a few 

 workers have attempted to discover physiological bases for mental dis- 

 turbances, but in the face of widespread opposition from groups that hold 

 the "psychic" hypothesis. A thorough consideration of the dramatic cure 

 of the mania of pellagra by niacin should do much to promote further in- 



