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pellagra (niacin deficiency, vitamin B3 deficiency)
The clinical syndrome resulting from deficiency of niacin.
Etiology:
- malnutrition
- dietary restriction
- alcoholism
Epidemiology:
- homeless
- rare in the U.S.
Pathology:
- diffuse inflammation & atrophy of gastrointestinal mucosa results in non-bloody diarrhea
Clinical manifestations:
1) photosensitivity:
a) recurring pruritic erythema on sun-exposed areas of skin
b) exfoliative dermatitis [2]
c) edema, thickening, dryness, roughness, hyperpigmentation, & eruption with desquamation may occur [2]
2) muscle weakness
3) gastrointestinal manifestations in 50%
- glossitis, stomatitis, dyspepsia
- intractable non-bloody diarrhea [1,2]
4) backpain
5) psychiatric manifestations develop late (40%)
- irritability
- anxiety
- delusions
- hallucinations
- apathy, melancholia
- fatigue
- depression
6) neurologic manifestations
- spastic paresis
- myelitis
- peripheral neuropathy [1]
- idiocy, cognitive impairment, dementia
Laboratory:
- serum niacin is low or undetectable
Management:
- niacin replacement therap
- 300 mg/day in divided doses for severeal weeks
- multivitamin & mineral supplementation prudent as patients are often deficient in several essential nutrients [1]
- prognosis
- response time varies according severity, but clinical improvement may be seen within a few days [1]
Related
nicotinic acid (niacin, vitamin B3, Niaspan)
General
vitamin B deficiency
References
- Kapoor R et al
D Is for Delay
N Engl J Med 2014; 371:2218-2223. December 4, 2014
http://www.nejm.org/doi/full/10.1056/NEJMcps1212211
- Yano H, Kinjo M
Pruritic Rash and Diarrhea
JAMA. 2021;325(11):1103-1104. March 16
PMID: 33724306
https://jamanetwork.com/journals/jama/fullarticle/2777445