Understanding Pellagra: Which among the following diseases is caused by deficiency of nicotinic acid?

October 24, 2025 •

4 min read

Historically, in the early 1900s, pellagra affected millions in the US, causing public health alarm due to its devastating symptoms. This once widespread nutritional disorder answers the question: Which among the following diseases is caused by deficiency of nicotinic acid? The illness is a severe deficiency of niacin, or vitamin B3, which is critical for cellular metabolism.

Quick Summary

Pellagra is a nutritional disorder resulting from a severe deficiency of niacin (nicotinic acid), leading to multi-systemic symptoms often described as the '4 Ds': dermatitis, diarrhea, dementia, and, if left untreated, death. It can arise from poor dietary intake or underlying medical conditions that impair nutrient absorption.

Key Points

Pellagra is the disease: Pellagra is the condition caused by a deficiency of nicotinic acid (niacin or vitamin B3).
The '4 Ds' of symptoms: Classic pellagra is characterized by dermatitis, diarrhea, dementia, and, if untreated, death.
Primary vs. secondary causes: The deficiency can be caused by a poor diet (primary pellagra) or by underlying health conditions that affect absorption (secondary pellagra).
Impact on body systems: The lack of niacin affects high-turnover areas of the body first, including the skin, digestive tract, and nervous system.
Diagnosis and treatment: Pellagra is diagnosed clinically and confirmed by a rapid response to niacin supplementation, which typically uses nicotinamide to avoid flushing.
Historically significant: Pellagra was a major public health issue in the early 20th century before food fortification became common.

What is Nicotinic Acid (Niacin)?

Nicotinic acid is one of the two primary forms of vitamin B3, with the other being nicotinamide. It is a water-soluble vitamin that plays a critical role in cellular function throughout the body, primarily as a component of the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). These coenzymes are essential for hundreds of metabolic reactions, including those involved in energy production, DNA repair, and antioxidant function. Without sufficient levels of niacin, the body's cells cannot function properly, leading to a host of health problems.

The Disease Caused by Nicotinic Acid Deficiency: Pellagra

The disease caused by a severe deficiency of niacin is known as pellagra, derived from the Italian words for 'rough skin'. It affects multiple systems, particularly the skin, digestive tract, and nervous system. In its classic presentation, pellagra is characterized by the "4 Ds": dermatitis, diarrhea, dementia, and death. While mostly eradicated in developed countries due to food fortification, it remains a concern in impoverished regions and in specific at-risk populations.

Symptoms of Pellagra: The 4 Ds

Dermatitis: The most visible symptom is a symmetrical, sun-sensitive rash that resembles a severe sunburn. It appears on exposed areas like the face, neck (known as Casal's necklace), hands (pellagrous gloves), and feet. Over time, the affected skin can become rough, scaly, and hyperpigmented.
Diarrhea: Pellagra affects the gastrointestinal tract, causing chronic diarrhea, abdominal pain, and inflammation of the mucous membranes. The tongue may become swollen and bright red, and sores can develop in the mouth.
Dementia: Neurological and psychiatric symptoms are common and can range from mild issues like irritability, apathy, and fatigue to severe cognitive decline. Memory loss, disorientation, confusion, and even delusions can occur.
Death: If left untreated, the multi-system damage caused by pellagra can eventually lead to death.

Causes of Pellagra

Pellagra can be classified into two main types: primary and secondary.

Primary Pellagra: This is caused by an inadequate dietary intake of both niacin and its amino acid precursor, tryptophan. It is historically associated with populations relying on corn as a dietary staple because corn is low in both niacin and tryptophan. Traditional nixtamalization (alkali treatment) of corn, practiced in some cultures, releases bound niacin, preventing pellagra.
Secondary Pellagra: This occurs when the body is unable to absorb or utilize niacin and tryptophan properly, even with sufficient dietary intake. Common causes include:
- Chronic alcoholism: Affects nutrient absorption and metabolism.
- Gastrointestinal disorders: Conditions like Crohn's disease and chronic diarrhea can lead to malabsorption.
- Genetic disorders: Hartnup disease is a rare hereditary disorder that impairs the absorption of tryptophan.
- Certain medications: Drugs such as isoniazid (used for tuberculosis) can interfere with the conversion of tryptophan to niacin.

Comparison of Primary vs. Secondary Pellagra


Feature	Primary Pellagra	Secondary Pellagra
Underlying Cause	Insufficient intake of niacin and tryptophan from diet.	Impaired absorption or metabolism of niacin and tryptophan due to underlying medical conditions.
Dietary Context	Common in areas where unfortified maize is the dietary staple and protein intake is low.	Can occur in individuals with seemingly adequate diets, but who have other health issues.
Risk Factors	Poverty, food insecurity, and monotonous diets.	Alcoholism, malabsorption syndromes, chronic illness, and specific medications.
Prevalence	Historically more common, but now primarily seen in specific regions or displaced populations.	More common in developed countries where dietary deficiency is rare.
Treatment Focus	Dietary correction and supplementation.	Addressing the underlying medical condition in addition to supplementation.

Diagnosis and Treatment

Diagnosing pellagra is often done clinically by observing the characteristic symptoms, particularly the sun-sensitive dermatitis. A dietary history can also provide crucial clues. Sometimes, urine tests can help confirm low niacin levels. The most definitive confirmation is a rapid improvement in symptoms after niacin supplementation.

The treatment for pellagra involves oral administration of niacin, often in the form of nicotinamide, which is preferred as it causes fewer side effects like skin flushing compared to nicotinic acid. Addressing the underlying cause is also crucial, especially in cases of secondary pellagra.

Prevention

The best way to prevent pellagra is to ensure a balanced diet rich in niacin and tryptophan. Fortification of staple foods like bread and cereals with niacin has been highly effective in eliminating widespread pellagra in industrialized nations. Excellent dietary sources of niacin include lean meat, poultry, fish, peanuts, and enriched grains. For those with risk factors, nutritional counseling and supplementation may be necessary to ensure adequate intake and absorption. Regular health screenings can also identify at-risk individuals before the condition progresses to its more severe stages.

World Health Organization Report on Pellagra Prevention

Disclaimer: This information is for general knowledge and should not be taken as medical advice. Consult with a healthcare professional before making any decisions about your health or treatment.

Frequently Asked Questions

The disease caused by a deficiency of nicotinic acid, also known as niacin or vitamin B3, is called pellagra.

The four classic symptoms of pellagra are often referred to as the '4 Ds': dermatitis (skin rash), diarrhea, dementia, and if left untreated, death.

Diagnosis is typically based on clinical symptoms and a patient's dietary history. A favorable response to niacin supplementation can confirm the diagnosis, and sometimes urine tests are used to check niacin levels.

Primary pellagra is caused by a diet lacking in niacin and tryptophan, while secondary pellagra is caused by an underlying condition that prevents the body from absorbing or using niacin correctly.

Pellagra is treated with oral niacin supplementation, most commonly with nicotinamide. A balanced diet is also recommended, and any underlying conditions contributing to the deficiency must be addressed.

Good dietary sources of niacin include lean meat, poultry, fish, peanuts, seeds, and enriched grains and cereals.

Pellagra is rare in industrialized countries due to food fortification. However, it still occurs in areas of food insecurity or in individuals with conditions like alcoholism or malabsorption.