Aetiology

Pellagra is rare in the UK as niacin occurs in many plant and animal foods and can also be synthesised from tryptophan.

Causes of pellagra:

• a monotonous maize diet (maize is low in tryptophan)
• a very low protein diet
• conditions producing considerable loss of protein e.g. nephrotic syndrome

Other causes include:

• malabsorption e.g. coeliac disease
• isoniazid - isoniazid is a pyridoxine antagonist - this agent is essential for conversion of tryptophan to nicotinic acid
• Hartnup Disease
• carcinoid syndrome - consumption of tryptophan by serotonin producing tumour
• alcoholism