Pellagra
A niacin deficiency disease causing dermatitis, dementia, and death.
Pellagra is a disease that develops when the body does not get enough niacin, also known as vitamin B3. Its hallmark signs are often remembered as the four Ds: diarrhea, dermatitis, dementia, and death. The skin problems usually start on areas exposed to friction or sunlight, and the affected skin can become darker, stiff, peel, or bleed. Other symptoms include a swollen, red tongue, hair loss, trouble sleeping, weakness, confusion, aggression, poor coordination, nerve damage, and an enlarged, weakened heart. Sores in the mouth are also common.
There are two main types. Primary pellagra comes from a diet lacking enough niacin and the amino acid tryptophan, which the body uses to make niacin. Secondary pellagra happens when the body cannot properly use the niacin it gets. This can be caused by chronic alcoholism, long-term diarrhea, certain tumors (carcinoid syndrome), a genetic condition called Hartnup disease that reduces tryptophan absorption, or medications like isoniazid. Excess leucine, an amino acid, can also block niacin production. Conditions like Crohn’s disease or stomach surgery can prevent nutrient absorption and lead to pellagra as well.
Diagnosis is usually based on symptoms and can be supported by urine tests that measure tryptophan or niacin byproducts. A rapid improvement after taking nicotinamide or nicotinic acid supplements confirms the diagnosis. Treatment involves these supplements, with improvements often starting within a few days. A better diet is also recommended, and protecting the skin from sun with sunscreen and clothing is important during healing. Without treatment, pellagra can be fatal within four or five years.
The disease is most common in the developing world, especially in sub-Saharan Africa, where it is linked to poverty and malnutrition. It also appears in rural South America where people rely heavily on untreated corn (maize) as a staple food, since corn is low in both niacin and tryptophan unless it is processed through nixtamalization. The word "pellagra" comes from Lombardic origins, with "pell" from Latin for "skin," and "-agra" possibly meaning "like serum or holly juice" or a suffix for a disease, borrowed from Greek for "a hunting trap."
- type
- Disease
- cause
- Niacin (vitamin B3) deficiency
- symptoms
- Inflamed skin, diarrhea, dementia, sores in mouth
- treatment
- Nicotinic acid or nicotinamide supplementation
- primary type
- Due to diet lacking niacin and tryptophan
- secondary type
- Due to poor ability to use niacin (e.g., alcoholism, Hartnup disease)
Lore & Background
He explained that the disease causes dermatitis in exposed skin areas such as hands, feet, and neck and that the origin of the disease is poor diet and atmospheric influences.
Reader's Guide
Pellagra is significant as a classic example of a micronutrient deficiency disease linked to poverty and diet. Its history illustrates the importance of food preparation: Native American cultivators who first domesticated corn prepared it by nixtamalization, which makes niacin nutritionally available and prevents pellagra. When maize was cultivated worldwide and eaten as a staple without nixtamalization, pellagra became common. The disease was once common in the poorer states of the U.S. South, where its cyclical appearance in spring after meat-heavy winter diets led to it being known as 'spring sickness'. Without treatment, pellagra can kill within four or five years. Treatment with nicotinamide typically brings improvements within a few days. The disease remains a public health concern in developing regions, particularly sub-Saharan Africa, and among displaced populations dependent on food aid.
Did You Know?
- The word 'pellagra' comes from Lombardic; 'pell' arises from Latin pellis meaning 'skin', while '-agra' may derive from Lombardic agra or the Latinate suffix for maladies.
- Pellagra can be caused by excess leucine, which inhibits quinolinate phosphoribosyl transferase and the formation of nicotinic acid to nicotinamide mononucleotide.
- In the 2000s, pellagra outbreaks occurred in countries such as Angola, Zimbabwe, and Nepal.
- Pellagra was common among prisoners of Soviet labor camps (the gulags).
Frequently Asked Questions
What is Pellagra?
Pellagra is a nutritional deficiency disease that arises when the body does not receive enough niacin (vitamin B3). It is classified as a malnutrition-related illness rather than an infectious one.
What causes Pellagra?
The primary trigger is a diet insufficient in niacin and tryptophan, the amino acid the body can convert into usable niacin. Secondary causes include conditions that impair niacin utilization, such as chronic alcoholism or Hartnup disease.
What are the classic symptoms of Pellagra?
The disease is well known for its "four Ds": dermatitis (inflamed, scaly skin), diarrhea, dementia (progressive confusion and cognitive decline), and ultimately death if untreated. Patients may also develop painful sores inside the mouth.
How is Pellagra treated?
Treatment is straightforward: supplementing the patient with nicotinic acid or nicotinamide to restore adequate niacin levels. Because the condition is purely nutritional, symptoms generally reverse once proper supplementation is begun.
Where is Pellagra most common today?
It predominantly affects impoverished populations in the developing world, especially in sub-Saharan Africa, where it is tightly linked to food insecurity. In high-income countries it is now rare, typically surfacing only in individuals with severe alcoholism or specific metabolic disorders.
More in Public Health And Epidemiology 1-19
Spotted an error? Know more?
This is a living reference — every entry is fact-audited, and reader corrections feed straight into our audit queue. Suggest an edit · See this site's audit record