disease has major feature Decreased circulating vitamin B3 concentration skin disorder nutritional deficiency disease pellagra https://rarediseases.info.nih.gov/diseases/10014/pellagra https://www.malacards.org/card/pellagra SCTID:418279001 DOID:8457 MEDGEN:45364 GARD:0010014 MONDO:0019975 Pellagra is a nutritional disorder caused by a deficiency in niacin (vitamin B3) or its precursor (tryptophan) that is mainly observed in Asia and Africa where it is generally due to poor nutrition. It is characterized by dermatitis (symmetrical photodistributed erythema that may be accompanied by vesicles and bullae, and that develops into hyperkeratotic and hyperpigmented skin), gastrointestinal symptoms (diarrhea), and neuropsychiatric disorders (dementia). It can be life-threatening without a correct management. Orphanet:97352 ICD9:265.2 UMLS:C0030783 MedDRA:10029400 MESH:D010383 pellagra icd11.foundation:1108993080