Pellagra secondary

Thiamine, a water-soluble vitamin, is indicated in beriberi, anemia secondary to thiamine deficiency, polyneuritis secondary to alcoholism, pregnancy or pellagra, Wernicke s encephalopathy, and wet beri-beri with myocardial failure. 

Niacin deficiency, named Pellagra, is characterized by diarrhoea, dermatitis, dementia and death, which usually appear in this order. The clinical expressions of pellagra are diverse (Prousky et al. 2011). Diagnosis was, and still is, difficult due to the unpredictable appearance of the different signs and symptoms in individual patients (Prousky et al. 2011). Pellagra can be divided into primary and secondary forms. Primary pellagra results from inadequate niacin and/or tryptophan in the diet. Secondary pellagra occurs when other diseases or factors affect niacin requirements. 

Occurrence of delusory parasitosis is an extremely rare phenomenon in this deficiency state. This usually develops secondary to the patients complaints of pruritus and paraesthesias due to pellagra skin lesions. This is the reason why patients with such complaints are referred to a dermatologist rather than to a psychiatrist (Leung and Ungwari 2004). It seems that such patients are prone to develop delusory parasitic ideas independent of the skin lesions. However, delusional parasitosis is known for its resistance to antipsychotic treatment and such a rapid resolution of any delusion. 

McNeely, R. G. D. and Jones, N. W., Secondary pellagra caused by multiple argentaffin carcinoma of the ileum and jejunum. Gastroenterology 6, 443 (1946). 

Severe deficiency disease has only been reported in a single outbreak in infants fed overheated formula. However, a significant proportion of people in developed countries have marginal vitamin Bg status, and this may be associated with enhanced responsiveness to steroid hormone action and may be a factor in the development of hormone-dependent cancer of the breast, uterus, and prostate. A number of drugs have antivitamin activity, and prolonged use may lead to secondary development of pellagra, as a result of impaired tryptophan metabolism. 

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