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Overview

What Is Pellagra?

Pellagra is a disease caused by not having enough niacin, also called vitamin B3, in the body. This pellagra definition includes deficiency caused by poor nutrition, problems absorbing nutrients or conditions that affect how the body uses niacin. It can affect the skin, digestive system and nervous system. People with malnutrition, heavy alcohol use or certain digestive conditions may be at higher risk.

Symptoms

Pellagra Symptoms

Pellagra symptoms may develop gradually and can vary based on how severe the niacin deficiency is and what caused it. The classic pattern involves skin, digestive and nervous system changes, but not everyone has every symptom.

  • A sun-sensitive rash (pellagrous dermatitis) may develop on skin exposed to sunlight.
  • Skin may become darker, thicker, rough or cracked in affected areas.
  • Diarrhea may occur and can become persistent.
  • The mouth or tongue may become sore, red or swollen.
  • Loss of appetite may make it harder to maintain adequate nutrition.
  • Weakness and unusual tiredness may occur.
  • Confusion or problems with memory and thinking may develop.
  • Other neurologic changes can include irritability, numbness, tingling or poor coordination.

Causes

Causes of Pellagra

Pellagra develops when the body does not receive or cannot properly use enough niacin. Vitamin B3 comes from food and can also be made in limited amounts from tryptophan, an amino acid found in protein; problems with either supply or metabolism can contribute to niacin deficiency pellagra.

  • Severe dietary insufficiency can result from a very limited diet, malnutrition or prolonged food insecurity.
  • Malabsorption can prevent the digestive system from taking in enough niacin and other nutrients.
  • Alcohol use disorder can reduce food intake, impair absorption and interfere with niacin use.
  • Gastrointestinal disease or surgery can limit nutrient absorption or alter digestion.
  • Some medicines can interfere with niacin metabolism when used for a prolonged period.
  • Rare inherited metabolic disorders can affect the way the body processes tryptophan or niacin.

Risk Factors

Risk Factors for Pellagra

Some pellagra risk factors are preventable, such as inadequate nutrition or heavy alcohol use, while others are medical conditions that need evaluation and treatment. Having a risk factor does not mean someone will develop pellagra, but it can make vitamin B3 deficiency more likely.

  • A severely restricted or unbalanced diet may provide too little niacin and tryptophan.
  • Food insecurity, malnutrition or difficulty eating can increase the risk of deficiency.
  • Heavy alcohol use can affect dietary intake, absorption and vitamin metabolism.
  • Malabsorption disorders may prevent adequate absorption of niacin and other nutrients.
  • Bariatric or other gastrointestinal surgery may change how nutrients are absorbed.
  • Chronic illness can increase nutritional needs or interfere with eating and absorption.
  • Some medicines may interfere with niacin metabolism or contribute to deficiency.

Complications

Pellagra Complications

Without treatment, pellagra can worsen and affect the nervous system, gastrointestinal tract and overall nutrition. Early treatment is important because prolonged niacin deficiency can cause serious complications, especially when diarrhea, poor intake or another illness is also present.

  • Persistent neurologic impairment may affect memory, thinking, mood, sensation or coordination.
  • Severe diarrhea can lead to dehydration and dangerous changes in body salts.
  • Ongoing poor appetite and digestive symptoms can cause malnutrition and weight loss.
  • Confusion or delirium may develop as deficiency becomes severe.
  • Advanced untreated deficiency can lead to life-threatening illness.

Diagnosis

How Pellagra Is Diagnosed

Clinicians diagnose pellagra by reviewing the person’s medical and nutrition history and performing a physical examination. They may ask about diet, alcohol use, digestive symptoms, weight changes and medicines, while examining skin findings and checking for neurologic changes.

Laboratory tests may assess nutritional status and look for conditions that cause malabsorption or other deficiencies. Improvement after appropriate niacin treatment can support the diagnosis, but it should not replace a medical evaluation or investigation of the underlying cause.

Treatment & Management

Pellagra Treatment and Management

Clinicians treat pellagra with an appropriate form and dose of niacin or vitamin B3. The dose and route depend on the severity of illness, the person’s ability to take medicines by mouth and any underlying medical conditions.

  • Correcting inadequate nutrition helps restore niacin, protein, calories and other needed nutrients.
  • Treating malabsorption or another underlying disease helps prevent the deficiency from returning.
  • Addressing alcohol use can improve nutrition and reduce continued vitamin loss or poor absorption.
  • Replacing other identified vitamin or mineral deficiencies may be part of recovery.
  • Follow-up monitoring helps clinicians assess symptom improvement, nutrition and the response to treatment.

Prevention

Can Pellagra Be Prevented?

Many cases of pellagra can be prevented by meeting vitamin B3 needs through a varied diet and treating conditions that interfere with nutrition or absorption. People with ongoing nutritional risks may need an individualized plan from a clinician or dietitian.

  • Eat niacin-containing foods such as fish, poultry, meat, legumes, nuts, seeds and whole grains.
  • Follow individualized nutrition advice after gastrointestinal or bariatric surgery.
  • Seek support for heavy alcohol use and related nutrition problems.
  • Ask a clinician about supplementation when a medical condition or restricted diet makes it necessary.

Outlook and Prognosis

Pellagra Outlook and Prognosis

Pellagra is generally treatable when the deficiency is recognized and the cause is addressed. Skin and digestive symptoms may improve with treatment, while neurologic effects can take longer to resolve or may not fully reverse if the deficiency was severe or prolonged.

Follow-up helps monitor nutritional status, confirm that the underlying cause is being treated and watch for recurrence. Continued risk factors, such as malabsorption or heavy alcohol use, may require long-term medical and nutrition support.

When Should You See a Doctor

When Should You See a Doctor for Pellagra?

When to get care

Do not ignore possible pellagra

Seek prompt medical care for a sun-sensitive rash with diarrhea, severe weakness, confusion, inability to eat or drink, signs of dehydration or symptoms that are rapidly worsening.

Arrange a medical appointment for a persistent rash, diarrhea, mouth soreness, unexplained weight loss or neurologic changes. Evaluation is especially important for someone with malnutrition, heavy alcohol use or a condition that affects nutrient absorption.