Pellagra (disease)

Pellagra is a disease that results from a vitamin B3 (niacin) deficiency. Such a deficiency may stem from a poor diet, certain diseases, or some medications. Pellagra causes skin, digestive, and neurological problems and can lead to death. While it is relatively rare in North America and Europe, partly because many grain products are fortified with niacin, it still occurs in some food-limited populations. It was a significant problem in the eighteenth and nineteenth centuries in southern Europe and the Mediterranean until physicians studying outbreaks in the American South demonstrated its dietary cause in the early twentieth century.

Brief History

The word pellagra comes from the Italian words for "skin" (pelle) and "sour/rough/bitter" (agra). The disease received its name in 1771 from Francesco Frapolli, an Italian doctor who used the term to describe the characteristic rough skin caused by the disease. The condition was first described by a Spanish doctor, Gaspar Casal, in 1735 after he noticed many of the people living in rural poverty had a strange, shiny, and red rash on their hands and feet. He called it mal de la rosa, or "red sickness."

Casal was the first person on record to have asked people afflicted with the rough skin patches and shiny rash what they were eating. He discovered that many ate a diet that included a significant amount of corn. Corn, or maize, had been introduced to Europe after explorers brought it back from the New World in the fifteenth century. It quickly became a common food source for the poor because it was easy for farmers to grow. However, the connection between the consumption of maize and the increased incidence of pellagra was not fully made at this time because it was noted that Indigenous Americans did not have the sickness even though they also ate diets with large amounts of maize.

In addition to physical symptoms, that is, the rash, victims of pellagra suffered mental and emotional distress. Pellagra interrupted sleeping patterns and sometimes caused aggression. The rash worsened with exposure to the sun. Because of these symptoms, people with pellagra were often thought to be vampires, especially in eighteenth-century Europe. People suffering from pellagra were ostracized and restricted from participation in many activities.

The disease was first recorded in the United States in 1902. For almost forty years, people in the southern United States became frequent victims of pellagra. Estimates suggest that as many as 100,000 people died from the condition before it was correctly associated with a lack of niacin caused by eating a diet low in meat and high in corn. Joseph Goldberger, an American physician working with the US Public Health Service, is credited with making this connection. It was determined that Indigenous groups in North and Central America who ate diets high in maize (corn), treated and cooked their corn differently. The majority of their corn was consumed in tortillas, which were made by soaking the corn in lime water overnight in a process called nixtamalization. This changed the composition of the corn to make niacin more available, which prevented them from getting pellagra. People who ate corn as a significant portion of their diet without treating it this way, as Europeans and Americans in the southern United States did, became ill with pellagra.

Overview

Primary pellagra is caused by a diet lacking sufficient niacin or tryptophan, an amino acid that the body can convert into niacin. However, people may become sick with secondary pellagra in a few other ways. Alcoholism, cirrhosis of the liver, chronic digestive problems (such as ulcerative colitis and prolonged bouts of diarrhea), and some tumors can make it impossible for a person to absorb niacin even when they consume enough in their diet. Taking certain medications, such as isoniazid or azathioprine, and other drugs that interfere with niacin metabolism can also hinder niacin absorption. Secondary pellagra may also occur in Hartnup disease, carcinoid syndrome, or after some surgeries that reduce nutrient absorption.

Pellagra afflicts the body in three main ways. First, it causes dermatological symptoms, such as a rash that at first resembles a bad sunburn. This occurs on skin exposed to the sun, skin rubbed by clothing or other materials, or skin exposed to heat. The rash eventually turns reddish brown, and it may continue to itch or burn. Areas affected by the rash thicken and harden and start to crack and peel. Areas inside the mouth, such as the lips, tongue, and gums, may also split and bleed.

After the skin symptoms appear, a patient afflicted with pellagra often begins suffering from gastrointestinal symptoms such as diarrhea, abdominal pain, and vomiting. The patient may have a poor appetite as well. This, combined with the discomfort of pain and vomiting, may prevent the patient from eating and drinking, leading to further malnutrition and increasing the niacin deficiency.

As these symptoms persist, the patient may start to show signs of depression. While this may seem to be a reaction to the physical symptoms, the depression is actually an early sign of the neurological problems caused by pellagra. The patient may suffer from headaches and experience confusion, restlessness, and anxiety. In time, this can progress to disorientation, delusions, and psychosis, a lack of contact with reality. In the final stages of the disease, the patient can slip into a coma and die.

A patient who presents with signs of pellagra will be asked about their diet. Blood and urine tests to check niacin levels may support the diagnosis. Other tests may be used to determine secondary causes of pellagra.

Primary pellagra can often be treated successfully with the administration of oral niacin. Dietary improvements, including more meat protein, may be prescribed. The patient may require secondary treatments for skin sores from the rash. Secondary pellagra can be more difficult to treat because it is necessary to first treat the cause. Getting a patient to stop drinking, treating cirrhosis and any gastrointestinal conditions, or stopping medications that may be causing the niacin deficiency will be necessary. The patient will likely need to take niacin supplements to increase niacin to sufficient levels and replace that which has been depleted.

Bibliography

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