Pellagra is found worldwide but is more common in developing countries where poverty and malnutrition are more common (in part because the staple grains do not have sufficient niacin). On examination, patients may display neurologic symptoms such as disorientation, myoclonic jerks, tremors, insomnia, fatigue, depression, and central pontine myelinolysis. In addition, an erythematous, blistering rash may be seen, which may be pruritic or painful in the distribution of solar exposure, as well as glossitis, stomatitis, and muscular weakness (especially of the lower extremities). Patients may complain of nausea, vomiting and/or diarrhea, and gastrointestinal symptoms, which often precede the other manifestations.
Risk factors for developing pellagra include poverty, staple diet poor in niacin (maize, Indian millet, or jowar), eating disorders, alcohol abuse, malabsorption, medication (INH, pyrazinamide, carbamazepine, carbidopa, chloramphenicol, phenytoin, phenobarbital), chemotherapy (5-fluorouracil, 6-mercaptopurine, azathioprine), post-surgical complications (gastrectomy), carcinoid syndrome, Crohn disease, Hartnup disease, and hypothyroidism.
Experimentally, pellagra has been induced after 2 months of a niacin-deficient diet; death will occur in 4-5 years if left untreated.
E52 – Niacin deficiency [pellagra]
418186002 – Pellagra
- Drug-induced photosensitivity
- Pellagra lesions take up to 4 times longer to heal than sunburns.
- Phytophotodermatitis occurs in the area of contact with the plant material/extract and is usually linear or drop-like in shape.
- The lesions from glucagonoma are found on truncal areas, whereas lesions of pellagra occur on sun-exposed areas.
- Kwashiorkor often involves the hair and nails while pellagra spares these areas.
- The lesions of zinc deficiency are perioral and perineal but may resemble wet pellagra.
- Porphyria cutanea tarda
- Variegate porphyria
- Atopic dermatitis
- Systemic lupus erythematosus
- Dermatomyositis may have a neck lesion but will also have a periorbital heliotrope (purple) rash and atrophic dermal papules of dermatomyositis (formerly called Gottron papules) on the fingers.