Pellagra: What is the name of the disease caused by vitamin B3 deficiency?

January 13, 2026 •

4 min read

First identified in the 18th century, the disease now known as pellagra was once endemic in parts of Europe and the American South. Pellagra is the name of the disease caused by vitamin B3 deficiency, which is also known as niacin deficiency. Left untreated, it can lead to severe and systemic health problems affecting the skin, digestive tract, and nervous system.

Quick Summary

Pellagra is the disease resulting from a severe niacin deficiency, characterized by the classic '3 Ds': dermatitis, diarrhea, and dementia. It can arise from inadequate dietary intake or malabsorption issues.

Key Points

Pellagra Name: The disease caused by vitamin B3 (niacin) deficiency is called pellagra.
The Four Ds: The classic symptoms are dermatitis, diarrhea, dementia, and potentially death if left untreated.
Causes: Pellagra can be primary (due to poor diet) or secondary (caused by conditions that impair niacin absorption or metabolism).
At-Risk Groups: Those with alcoholism, certain GI diseases, or who rely on unfortified corn as a staple are at higher risk.
Photosensitive Rash: A distinctive, often symmetrical, rash appears on sun-exposed skin, including a collar-like rash on the neck.
Treatment: Replenishing niacin through supplements and improving diet typically resolves the condition.
Prevention: A balanced diet and treating underlying conditions are key to preventing pellagra.

Understanding Pellagra: The Disease of Niacin Deficiency

Pellagra is a systemic nutritional disorder resulting from a severe lack of niacin (vitamin B3) or its precursor, the amino acid tryptophan. Although now rare in industrialized countries due to fortified foods, it remains a serious health concern in food-insecure regions and among certain vulnerable populations. The name 'pellagra' comes from the Italian 'pelle agra', meaning 'sour skin' or 'rough skin', referring to its characteristic skin symptoms. The effects of pellagra are widespread because niacin is a critical component of coenzymes essential for cell metabolism throughout the body.

The Classic Signs and Symptoms: The Four Ds

Pellagra is most famously known for its classic quartet of symptoms, often referred to as 'the four Ds': dermatitis, diarrhea, dementia, and if left untreated, death. The symptoms typically appear progressively, with some manifesting earlier than others. Not every patient will develop all four signs, but their presence is a key diagnostic indicator.

Dermatitis

This is often the earliest and most recognizable symptom, typically appearing on sun-exposed areas of the skin.

Photosensitivity: The skin develops a rash similar to a sunburn, often in a symmetric pattern.
Distinctive Locations: Rashes commonly appear on the face, neck (forming a band known as Casal's necklace), hands (pellagrous gloves), and feet (pellagrous boots).
Progression: The rash can become rough, scaly, and hyperpigmented over time.

Diarrhea

Gastrointestinal issues often precede or occur alongside the skin manifestations. The entire digestive tract is affected by inflammation.

Digestive Distress: This includes abdominal pain, nausea, and persistent, sometimes bloody, diarrhea.
Oral Symptoms: The tongue can become swollen, bright red, and sore (glossitis), with sores developing in the mouth.

Dementia

Neurological symptoms are a late manifestation and indicate severe deficiency. The brain and nervous system are affected as cells are deprived of energy.

Early Signs: These include vague symptoms such as fatigue, lethargy, anxiety, depression, and poor concentration.
Advanced Stages: Can progress to confusion, disorientation, memory loss, and hallucinations.

Death

If the disease is not diagnosed and treated, the progressive systemic damage can ultimately lead to death.

Primary vs. Secondary Pellagra: Understanding the Causes

Pellagra can occur for different reasons, which fall into two main categories.

Primary Pellagra This form is caused by an inadequate dietary intake of niacin and tryptophan. It is historically associated with populations reliant on corn as a staple food, as untreated corn contains niacin in a bound form that the body cannot easily absorb. In Central and South American cultures, nixtamalization (soaking corn in an alkaline solution) frees the bound niacin, which is why pellagra was rare in these regions.

Secondary Pellagra This occurs when the body cannot properly absorb or utilize the niacin and tryptophan that are consumed in the diet. This form is more common in industrialized nations and can be caused by:

Chronic alcoholism
Gastrointestinal diseases (e.g., Crohn's disease, prolonged diarrhea)
Certain medications (e.g., isoniazid used for tuberculosis treatment)
Genetic disorders (e.g., Hartnup disease)
Carcinoid syndrome, which diverts tryptophan from niacin production
HIV infection

Diagnosing and Treating Pellagra

Diagnosis is typically based on a clinical assessment of symptoms and a patient's dietary history. A healthcare provider may order a urine test to measure niacin metabolites, but a rapid and positive response to niacin supplementation is often a key confirmation.

Treatment is straightforward and involves correcting the underlying deficiency. The standard approach includes:

Niacin Supplements: High doses of niacinamide (a form of niacin) are typically administered, either orally or via injection in severe cases. Nicotinamide is often preferred as it has a lower risk of the flushing side effect associated with nicotinic acid.
Nutritional Support: A balanced diet rich in protein, tryptophan, and other B-complex vitamins is recommended, as niacin deficiency often co-occurs with other nutritional issues.
Addressing the Underlying Cause: For secondary pellagra, treating the root cause (such as alcoholism or a gastrointestinal disorder) is crucial for long-term recovery.

Recovery can be rapid once treatment begins, with many patients showing improvement in gastrointestinal and skin symptoms within days to weeks. Severe neurological damage, however, may be irreversible.

Comparison of Primary and Secondary Pellagra


Feature	Primary Pellagra	Secondary Pellagra
Cause	Inadequate dietary intake of niacin or tryptophan.	Impaired absorption or metabolism of niacin and/or tryptophan.
Risk Factors	Poverty, limited food variety, reliance on unfortified corn.	Alcoholism, chronic diarrhea, certain medications (e.g., isoniazid), GI diseases.
Incidence	More common in developing nations or food-insecure regions.	More frequent in industrialized countries among specific at-risk groups.
Treatment Focus	Niacin/tryptophan supplementation and dietary education.	Niacin supplementation plus treatment of the underlying health condition.

Conclusion

While rarely seen in developed countries today thanks to food fortification, pellagra remains a critical concern in certain global contexts and for at-risk individuals. Recognizing the characteristic symptoms of dermatitis, diarrhea, and dementia is vital for early diagnosis and treatment. By addressing the deficiency with niacin supplementation and a balanced diet, the progression of this potentially fatal disease can be halted and reversed. Understanding the difference between primary (diet-related) and secondary (malabsorption/metabolism-related) pellagra is also important for effective, comprehensive management.

Authoritative Source: Pellagra: Definition, Symptoms & Treatment - Cleveland Clinic

Frequently Asked Questions

The early signs of vitamin B3 deficiency often include fatigue, lethargy, loss of appetite, and mood changes such as anxiety or depression. Oral symptoms like a red, swollen tongue and mouth sores can also appear early.

Pellagra is primarily diagnosed based on clinical signs, symptoms, and dietary history. A healthcare provider may also use a urine test to measure niacin metabolites. A swift improvement in symptoms after niacin supplementation is often confirmation of the diagnosis.

The most effective treatment for pellagra is to replace the missing niacin with supplements, typically nicotinamide. A high-protein diet rich in B-complex vitamins is also essential for complete recovery. Any underlying conditions causing the deficiency must also be addressed.

Yes, pellagra is both treatable and preventable. With proper treatment, most symptoms improve rapidly, often within a couple of weeks. However, severe neurological damage or dementia may not be reversible.

Foods rich in vitamin B3 include red meat, poultry, fish (like salmon and tuna), legumes, peanuts, enriched bread and cereals, and liver. The body can also synthesize niacin from the amino acid tryptophan, found in protein-rich foods.

Pellagra is rare in developed countries primarily because many staple foods, such as bread and cereals, are fortified with niacin. Additionally, varied diets are more common, reducing the risk of a severe deficiency.

In developed nations, those at highest risk include individuals with chronic alcoholism, malabsorption issues from GI diseases, HIV, anorexia nervosa, or those taking certain medications like isoniazid. It also persists in food-limited populations worldwide.