A 16-year-old boy with Crohn disease is brought to the office due to diarrhea and rash. For the last 3 months, the patient has had watery, nonbloody diarrhea 3 or 4 times daily as well as a rash on his distal arms and legs that sometimes becomes intensely pruritic. He has also had a difficult time concentrating in school and has been less interested in his usual activities, such as skateboarding and rollerblading. Vital signs are normal. Physical examination reveals a smooth, red tongue. The abdomen is soft, is nontender, and has no hepatosplenomegaly. A dry, erythematous, and hyperpigmented rash is located on the distal arms and legs. The affected area has thickened skin and sharp lines of demarcation. Neurologic examination is normal. This patient's symptoms are most likely due to a deficiency of which of the following vitamins?

Question

A 16-year-old boy with Crohn disease is brought to the office due to diarrhea and rash.  For the last 3 months, the patient has had watery, nonbloody diarrhea 3 or 4 times daily as well as a rash on his distal arms and legs that sometimes becomes intensely pruritic.  He has also had a difficult time concentrating in school and has been less interested in his usual activities, such as skateboarding and rollerblading.  Vital signs are normal.  Physical examination reveals a smooth, red tongue.  The abdomen is soft, is nontender, and has no hepatosplenomegaly.  A dry, erythematous, and hyperpigmented rash is located on the distal arms and legs.  The affected area has thickened skin and sharp lines of demarcation.  Neurologic examination is normal.  This patient's symptoms are most likely due to a deficiency of which of the following vitamins?

Quizplus · Accepted Answer

11ec25c8_d68a_7df8_bc81_b70901dde23c_MD0003_00 Niacin, an essential nutrient found primarily in meat, fish, and legumes, is absorbed in the stomach and small intestine. Niacin (vitamin B₃) deficiency leads to pellagra, which is characterized by the 4Ds: diarrhea, dermatitis, dementia, and if severe, death. Pellagra is common in resource-limited countries where the main diet is grain or corn but can also be seen in malabsorptive bowel disease (eg, Crohn disease), anorexia nervosa, and alcoholism. Pellagra typically presents with gastrointestinal issues, such as nausea, abdominal pain, epigastric discomfort, and watery diarrhea. The characteristic photosensitive dermatitis occurs in sun-exposed areas and resembles a sunburn (ie, erythematous, well-demarcated). Over time, the affected skin becomes hyperpigmented and thickened. Like several other nutrient deficiencies, pellagra is associated with atrophic glossitis, which presents with a smooth, red tongue. Neurologic manifestations range from poor concentration and irritability to depression and dementia. Death can occur in severe, untreated niacin deficiency. Treatment is niacin replacement. (Choice A) Deficiency of cobalamin (vitamin B₁₂) causes macrocytic anemia, glossitis, and neuropsychiatric symptoms (eg, shuffling gait, paresthesias, depression). Dermatitis is not associated with cobalamin deficiency. (Choice C) Pyridoxine (vitamin B₆) deficiency is rare and can cause irritability and depression, glossitis, peripheral neuropathy, and seborrheic dermatitis. Unlike the dermatitis of niacin deficiency, the dermatitis of pyridoxine deficiency is not photosensitive. ₆ (Choice D) Riboflavin (vitamin B₂) deficiency is a complication of malabsorptive bowel disease and can lead to cheilosis, glossitis, and seborrheic dermatitis. A photosensitive rash does not occur in riboflavin deficiency. (Choice E) Thiamine (vitamin B₁) deficiency causes beriberi (ie, peripheral neuropathy with or without cardiac involvement) or Wernicke-Korsakoff syndrome, a neurologic disease most common among patients with alcoholism. Neither is associated with dermatitis. Educational objective: Niacin (vitamin B₃) deficiency causes pellagra, which is characterized by diarrhea, a photosensitive dermatitis, and neurologic symptoms ranging from impaired concentration to dementia. Severe cases can be fatal. References: Pellagra: a review with emphasis on photosensitivity. (http://www.ncbi.nlm.nih.gov/pubmed/21128910) Niacin. (http://www.ncbi.nlm.nih.gov/pubmed/27184282) B vitamins and the brain: mechanisms, dose and efficacy-a review. (http://www.ncbi.nlm.nih.gov/pubmed/26828517) Common tongue conditions in primary care. (http://www.ncbi.nlm.nih.gov/pubmed/20187599)

A 16-Year-Old Boy with Crohn Disease Is Brought to the Office