Pellagra is a systemic disease caused by a severe deficiency of niacin (vitamin B3). It affects the whole body and can eventually lead to death. Primary pellagra is caused by a lack of niacin in your diet. It usually occurs in poor and food-limited populations. Secondary pellagra can occur when your body is unable to absorb the niacin you eat.
Pellagra is a disease caused by a deficiency of niacin, otherwise known as vitamin B3. It’s a form of malnutrition — specifically, micronutrient undernutrition. Niacin is crucial to cell functioning throughout your body, and the lack of it shows up in symptoms throughout your body, including your skin, mouth, bowels and brain. If left untreated, pellagra can cause lasting damage to your nervous system and even death.
Niacin is found in many food sources, and most people who eat a balanced diet get enough of it. But primary pellagra — from inadequate dietary intake — is still a significant problem in impoverished and food-limited populations. In the industrialized world, niacin deficiency is more likely to occur from secondary causes — from health conditions or substances that prevent your body from absorbing or using niacin.
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Your body uses niacin (vitamin B3) to convert food calories into energy. The niacin you eat is absorbed through your small intestine into your body tissues, where it’s converted to a coenzyme called nicotinamide adenine dinucleotide (NAD). A coenzyme is an enzyme agent. It works together with enzymes to catalyze chemical reactions. More than 400 different enzymes in your body depend on coenzyme NAD to function.
Coenzyme NAD helps transfer the potential energy in macronutrients — carbohydrates, proteins and fats — into the kind of energy your cells can use (adenosine triphosphate, or ATP). Your cells depend on it for energy to function, and body systems with higher energy requirements depend on it more. NAD is also involved in a variety of specific cellular functions, including DNA repair and cellular communication.
Because NAD is so heavily involved in providing fuel to cells, the lack of it tends to show up first in the body systems with the highest energy requirements or cell turnover rates. That means your skin, the mucous lining of your gastrointestinal tract, and your brain. Classic pellagra shows up as a collection of symptoms that healthcare providers describe as the “3 Ds”: diarrhea, dermatitis, and dementia. Some add a fourth “D” to include death. Death can occur if pellagra is left untreated for several years.
Diarrhea occurs when the mucous lining of your intestines fails to replenish itself fast enough. Without this mucosa, the intestines can’t digest properly, and they can’t protect themselves from irritation and inflammation. Chronic inflammation affects the mucous lining along your entire gastrointestinal tract, from your mouth to bowels. This leads to gastrointestinal symptoms such as stomach pain and indigestion, as well as symptoms of oral mucositis, which include mouth sores and a red, swollen tongue.
Pellagra also produces a distinctive type of dermatitis, particularly on sun-exposed areas of the body, such as the face, neck, arms, legs, hands and feet. Deprived of energy resources, the skin cells become more photosensitive. Dermatitis begins with rashes that resemble a sunburn, then progresses to rough, scaly, hyper-pigmented plaques. One telltale feature is a dark, hyper-pigmented collar around the neck. It’s called Casal’s collar, after the Spanish physician Don Gaspar Casal who first identified pellagra among the Spanish peasants in 1735.
Pellagra is a systemic disease, affecting the body as a whole as cells are deprived of the energy they need to perform bodily functions. This will eventually affect the brain and nervous system. Early symptoms may be vague. They may include lethargy, apathy, and difficulty concentrating, or they may look more like anxiety or depression. Over time, symptoms progress to confusion and delusions. Severe cases may lead to permanent dementia, as well as neurological damage resulting in balance and coordination problems, muscle twitches and tremors.
Historically, pellagra has occurred in poor populations throughout the world, including Europe, Africa, Asia and the Southern United States. It usually occurs in populations where the diet is very limited, especially where protein is scarce and corn is the staple food. Protein and the amino acids that come from protein are important for metabolizing niacin. And while many grains contain niacin, the niacin in corn is in a “bound” form that’s hard for our bodies to absorb.
In Central and South America, the traditional method for making corn tortillas involves soaking the corn in limewater overnight. This process unbinds the niacin in the corn and makes it available to absorb. For this reason, pellagra has rarely been seen in these populations. This was not the case in the Southern United States in the early 1900s, however, when pellagra was so pervasive that the U.S. Congress asked the Surgeon General to investigate the disease.
The Surgeon General appointed Joseph Goldberger, a medical officer in the US Public Health Service, to lead the investigation. Goldberger’s research led to the discovery that pellagra was caused by poor diet (published in 1923). The following decade, American biochemist Conrad A. Elevjhem discovered that the missing nutrient was niacin. By the mid-century, bread and cereal products in the United States were routinely fortified with niacin, a practice that continues today.
Today, pellagra in the United States is rare, occurring in less than 1%, and is usually due to secondary causes, such as alcohol use. The same is true in other industrialized Western nations, many of which have adopted the practice of fortifying bread and cereal products. However, primary pellagra does still very much exist in less developed regions of the world, especially tribal populations where corn continues to be the staple. It’s most commonly found in India, China and sub-Saharan Africa today.
The primary cause of pellagra is an inadequate diet. You can get your vitamin B3 from a wide range of foods, but people who don’t have enough food choices may lack certain nutrients.
You can also get pellagra from secondary causes, meaning other health conditions that prevent your body from absorbing or using niacin. Some of these include:
Your healthcare provider will examine you and your symptoms and ask you about your medical history and diet. When they suspect pellagra, they may order a urine test to confirm it. Levels of certain chemicals in your urine can tell them if your body has enough niacin. They may also confirm pellagra by treating you with niacin supplements and seeing if that helps.
Since pellagra is a deficiency of niacin (vitamin B3), it’s cured by replacing the missing nutrient. With niacin supplements, most people begin to improve right away. You may need additional treatment for symptoms such as skin sores and mouth sores. If your pellagra was caused by a pre-existing health condition, you’ll need treatment for that too.
If you take them as prescribed, you shouldn’t have any side effects from the supplements. Side effects can occur if you overdose, but it’s hard to overdose when you’re deficient.
Side effects can include:
A well-balanced diet is the simplest way to ensure adequate nutrition. When food choices are limited, enriched foods and dietary supplements can help. A B-complex vitamin supplement provides enough niacin for most healthy adults. The recommended daily dose of niacin is about 15 milligrams.
The best food sources of niacin are:
If you have a chronic health condition that predisposes you to pellagra, you may need to discuss long-term prevention with your healthcare provider. This may involve diet, supplements or changes to your medications.
With supplements, most people begin to improve in a few days. Gastrointestinal symptoms are the first to heal, usually within the first week. Skin and mouth sores begin to heal within two weeks. Some advanced cases may take longer to heal. Severe nerve damage and dementia may be irreversible.
Going forward, healthcare providers recommend maintaining a balanced diet to prevent primary pellagra. Niacin deficiency often occurs with other micronutrient deficiencies. These can all be improved with an adequate diet. Some people may need nutritional education or additional support.
Secondary pellagra can be trickier to treat. Although supplements often help, they may not help enough if your body is unable to metabolize niacin effectively. Recovery in these cases depends on isolating and treating the underlying condition that is causing pellagra. This can be a long process, depending on the condition.
A note from Cleveland Clinic
Although primary pellagra has been mostly eradicated in the developed world, it’s still endemic in less developed populations where food sources are limited. These populations could benefit from the kinds of nutritional support that helped us beat pellagra not too long ago, such as fortified food products, supplements, education and other resources.
In our world, secondary niacin deficiency remains a risk for those affected by alcoholism or by certain health conditions that prevent the body from metabolizing niacin. It’s important to remember that while nutrition begins with diet, it ends in the body, where many things have to go right. If you have symptoms of things going wrong, particularly in your digestive system, seek medical care. Even a small vitamin deficiency can have a domino effect on your health.
Last reviewed by a Cleveland Clinic medical professional on 07/18/2022.
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