An Unexplained Rash and Diarrhea in a Young Man With Poor Oral Intake

Mohamad Kabach, MD, Sandeep Dayanand, MD, Julio Mercado, MD, and Daniel M. Lichtstein, MD, MACP

A 23-year-old male college student with a prolonged history of poor oral intake presented to the emergency department with intermittent lower-extremity pain, progressive weakness, and a “pins-and-needles” sensation in both hands associated with scaly rash. He also complained of tongue swelling, mood changes, and worsening watery diarrhea for the past 2 months.


At presentation, his vital signs were within normal limits, he appeared cachectic, and his body mass index was 16 kg/m2. He had moderate enlargement of his tongue with glossitis (Figure 1) and decreased sensation of the tips of both hands. A scaly dermatitis in a glove pattern distribution was also present (Figure 2). The remainder of his physical examination findings were unremarkable.

Upon questioning, the patient stated that he typically eats only one meal a day consisting of lettuce and corn, and he had not eaten meat products for more than 10 years.

What do you suspect is causing this man’s symptoms?


Answer on next page.



Answer: Pellagra

The man was admitted to the hospital for further evaluation and workup. Given his reported poor oral intake, his low BMI and clinical presentation, vitamin B3 deficiency was suspected, and he was started on niacin replacement therapy. His niacin level was 0.56 µg/mL (reference range, 0.50-8.45 µg/mL); however, he had received niacin replacement (500 mg orally) prior to the test having being done.

He was discharged in 24 hours with significant improvement of his symptoms. He refused psychiatric consultation for a presumed eating disorder, but he received nutritional counseling in the hospital before discharge.

At a follow-up appointment with his primary care physician, all of his symptoms had resolved, and his niacin level was in the normal range at 6.2 µg/mL.


Pellagra (from the Italian pelle, skin, and agra, rough; also called corn diet disease) is very rare in the United States. It is a potentially fatal nutritional disease with gastrointestinal, cutaneous, and neuropsychiatric manifestations. It is caused by severe malnutrition associated with vitamin B3 (niacin) deficiency and possibly by excessive intake of leucine found in corn and cereals.1 It may also result from alterations in protein metabolism in disorders such as carcinoid syndrome or Hartnup disease.

Pellagra is characterized by diarrhea, dementia, and dermatitis.2 The dermatitis of pellagra involves sun-exposed skin in a bilateral and symmetric pattern.3 Because of the diversity of the presenting signs and symptoms and the rarity of this disease in the United States, diagnosis is difficult without an appropriate index of suspicion. The appearance of a glove-like rash on the hands provides a clue to a unifying diagnosis in the presence of other typical signs and symptoms. Taken together, dermatitis (especially in sun-exposed areas), dementia, and diarrhea as presenting manifestations should suggest pellagra, especially when accompanied by factors associated with poor nutrition. Importantly, peripheral neuropathy also has been described in patients with pellagra4 and was noted in our patient.

This disease may be seen in patients with eating disorders such as anorexia nervosa and from severe malnutrition due to social or neuropsychiatric illnesses. Clinicians should be reminded of the classical presentation of pellagra as consisting of the 3 D’s, diarrhea, dermatitis and dementia, and to not overlook this significant but treatable disease.


Mohamad Kabach, MD, is at the University of Miami Miller School of Medicine, Palm Beach Regional Campus, in Atlantis, Florida.

Sandeep Dayanand, MD, is at the University of Central Florida School of Medicine in Orlando.

Julio Mercado, MD, is at the University of Miami Miller School of Medicine, Palm Beach Regional Campus, in Atlantis, Florida.

Daniel M. Lichtstein, MD, MACP, is a professor of medicine and regional dean for medical education at the University of Miami Miller School of Medicine in Miami, Florida.


  1. Bapurao S, Krishnaswamy K. Vitamin B6 nutritional status of pellagrins and their leucine tolerance. Am J Clin Nutr. 1978;31(5):819-824.
  2. Hegyi J, Schwartz RA, Hegyi V. Pellagra: dermatitis, dementia, and diarrhea. Int J Dermatol. 2004;43(1):1-5.
  3. Wan P, Moat S, Anstey A. Pellagra: a review with emphasis on photosensitivity. Br J Dermatol. 2011;164(6):1188-1200.
  4. Rivlin RS. Disorders of vitamin metabolism: deficiencies, metabolic abnormalities, and excesses. In: Wyngaarden JB, Smith LH Jr, eds. Cecil Textbook of Medicine. 18th ed. Philadelphia, PA: WB Saunders; 1998:1231-1233.