History: A 14 yr female presented to ED with 6 weeks h/o well-defined darkening and thickening of the hands, feet, ankles, neck, and the upper trunk region including upper chest and back. She had similar lesions but milder form on lips and periorbital region. The affected area of the skin was said to get exacerbated after exposure or re-exposure to sunlight. She also complaint of recurrent episodes of passage of loose watery stools. What’s the diagnosis?
Pellagra is a disease caused by a lack of vitamin niacin (vitamin B3).
Symptoms include inflamed skin, diarrhea, dementia, and sores in the mouth. Areas of the skin exposed to either sunlight or friction are typically affected first. Over time affected skin may become darker, stiffen, peel, or bleed.
There are two main types of pellagra, primary and secondary.
Primary pellagra is due to a diet that does not contain enough niacin and tryptophan.
Secondary pellagra is due to a poor ability to use niacin within the diet. This can occur as a result of alcoholism, long-term diarrhea, carcinoid syndrome, Hartnup disease, and a number of medications such as isoniazid. Diagnosis is typically based on symptoms and may be assisted by urine testing.
Treatment is with either niacin or nicotinamide supplementation. Improvements typically begin within a couple of days. General improvements in diet.