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Skin manifestations of Pellagra

Pellagra is a a vitamin deficiency disease caused by chronic lack of nicotinic acid (niacin, vitamin B3) or its precursor, tryptophan.Niacin is required for most cellular processes.

CAUSE of Pellagra:
Inadequate niacin and/or tryptophan in the diet mainly seen in developing countries or poverty stricken areas "called Primary pellagra".But usually there is something prevents Niacin absorption and processing and causes secondary pellagra such as:
• Alcoholism, malabsorption, anorexia nervosa, Prolonged diarrhoea, Liver cirrhosis, Drugs e.g. isoniazid, azathioprine

• Carcinoid tumors (excessive use of tryptophan, which produces serotonin)

Symptoms and signs of Pellagra is classically described by "the four D's": diarrhea, dermatitis, dementia and If left untreated, death.

Skin manifestations and clinical finding of Pellagra:
-At first there is reddened skin with superficial scaling in areas exposed to sunlight, heat & friction. This may resemble severe sunburn then gradually subsides leaving a dusky brown-red colouration .
-The rash is usually symmetrical with a clear edge between affected and unaffected skin and sometimes may be itching or burning sensation
-Other features sometimes present include cheilosis, glossitis, angular stomatitis, and oral or perianal sores.

Legs and feet of a patient with niacin deficiency. A, Before therapy. B, After therapy.
(From Swartz MH: Textbook of Physical Diagnosis, 5th ed. Philadelphia, WB Saunders, 2006.)

TREATMENT of Pellagra:
• Nutritional supplementation with niacin will improve the appearance of skin lesions

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