Pellagra: Difference between revisions
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==Background== | ==Background== | ||
*Pellagra is the deficiency of Niacin (Vitamin B3). | *Pellagra is the deficiency of Niacin (Vitamin B3). | ||
*Niacin is an important factor for the production of NADH and NADPH, which are important for redox reactions. | *[[Niacin]] is an important factor for the production of NADH and NADPH, which are important for redox reactions. | ||
**Deficiency therefore affects tissues with high turnover, including skin, GI tract and brain | **Deficiency therefore affects tissues with high turnover, including skin, GI tract and brain | ||
*Niacin is either consumed in the diet or converted from tryptophan by the hepatic kynurenine pathway in the liver. | *Niacin is either consumed in the diet or converted from tryptophan by the hepatic kynurenine pathway in the liver. | ||
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===Drugs that inhibit niacin production=== | ===Drugs that inhibit niacin production=== | ||
*Azathioprine | *[[Azathioprine]] | ||
*Chloramphenicol | *[[Chloramphenicol]] | ||
*Ethionamide | *Ethionamide | ||
*5-Fluorouracil | *5-Fluorouracil | ||
*Isoniazid | *[[Isoniazid]] | ||
*6mercaptopurine | *6mercaptopurine | ||
*Pyrazinamide | *[[Pyrazinamide]] | ||
===Conditions that decrease niacin GI absoprtion=== | ===Conditions that decrease niacin GI absoprtion=== | ||
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*[[Ulcerative colitis]] | *[[Ulcerative colitis]] | ||
*[[Cirrhosis]] | *[[Cirrhosis]] | ||
*Gastrectomy patients | *[[Weight loss surgery complications|Gastrectomy]] patients | ||
==Clinical Features== | ==Clinical Features== | ||
[[File:Casal's_necklace.png|thumb|Casal's Necklace in a case of isoniazid-induced pellagra.]] | [[File:Casal's_necklace.png|thumb|Casal's Necklace in a case of isoniazid-induced pellagra.]] | ||
''Niacin deficiency classically causes the 4 D's: Dermatitis, Diarrhea, Dementia and Death.'' | ''Niacin deficiency classically causes the 4 D's: Dermatitis, Diarrhea, Dementia and Death.'' | ||
*Skin photosensitivity and rash. Erythematous and scaly. May be mistaken for sunburn. | *Skin photosensitivity and [[rash]]. Erythematous and scaly. May be mistaken for sunburn. | ||
**secondary to UV damage and decreased repair | **secondary to UV damage and decreased repair | ||
**"Casal's Necklace." Reddish rash surrounding the neck, and on the hands and feet. This is a photosensitivity rash in the exposed areas of the neck. Originally described by Gaspar Casal in 1735. | **"Casal's Necklace." Reddish rash surrounding the neck, and on the hands and feet. This is a photosensitivity rash in the exposed areas of the neck. Originally described by Gaspar Casal in 1735. | ||
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**secondary to decreased cell turnover | **secondary to decreased cell turnover | ||
*Neurological symptoms | *Neurological symptoms | ||
**"Pellagra encephalopathy," depression, anxiety, altered mental status, hallucinations, delusions, affective disorders, cognitive dysfunction. | **"Pellagra [[encephalopathy]]," [[depression]], [[anxiety]], [[altered mental status]], [[hallucinations]], delusions, affective disorders, cognitive dysfunction. | ||
*Niacin deficiency is often associated with chronic alcohol use secondary to nutritional deficiency and malabsorption. | *Niacin deficiency is often associated with chronic [[alcohol]] use secondary to nutritional deficiency and malabsorption. | ||
==Differential Diagnosis== | ==Differential Diagnosis== | ||
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==Management== | ==Management== | ||
Niacin supplementation. | *[[Niacin]] supplementation. | ||
==Disposition== | ==Disposition== | ||
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[[Category:Dermatology]] | [[Category:Dermatology]] | ||
[[Category:FEN]] | |||
Revision as of 01:01, 28 September 2019
Background
- Pellagra is the deficiency of Niacin (Vitamin B3).
- Niacin is an important factor for the production of NADH and NADPH, which are important for redox reactions.
- Deficiency therefore affects tissues with high turnover, including skin, GI tract and brain
- Niacin is either consumed in the diet or converted from tryptophan by the hepatic kynurenine pathway in the liver.
- Neurological symptoms can also be exacerbated by supplementation by other B vitiamins, particularly B1, B2, B6, and B12. Mechanism is unknown but may be secondary to the increased demand of NAD.
Drugs that inhibit niacin production
- Azathioprine
- Chloramphenicol
- Ethionamide
- 5-Fluorouracil
- Isoniazid
- 6mercaptopurine
- Pyrazinamide
Conditions that decrease niacin GI absoprtion
Clinical Features
Niacin deficiency classically causes the 4 D's: Dermatitis, Diarrhea, Dementia and Death.
- Skin photosensitivity and rash. Erythematous and scaly. May be mistaken for sunburn.
- secondary to UV damage and decreased repair
- "Casal's Necklace." Reddish rash surrounding the neck, and on the hands and feet. This is a photosensitivity rash in the exposed areas of the neck. Originally described by Gaspar Casal in 1735.
- GI symptoms
- secondary to decreased cell turnover
- Neurological symptoms
- "Pellagra encephalopathy," depression, anxiety, altered mental status, hallucinations, delusions, affective disorders, cognitive dysfunction.
- Niacin deficiency is often associated with chronic alcohol use secondary to nutritional deficiency and malabsorption.
Differential Diagnosis
Other Rash
- Acute generalized exanthematous pustulosis
- Allergic reaction
- Aphthous stomatitis
- Atopic dermatitis
- Coxsackie
- Dermatitis herpetiformis
- Exfoliative erythroderma
- Impetigo
- Pellagra
- Pityriasis rosea
- Serum Sickness
- Tinea capitus
- Tinea corporis
- Vitiligo
Vitamin deficiencies
- Vitamin A deficiency
- Vitamin B deficiencies
- Vitamin B1 deficiency (Thiamine)
- Vitamin B3 deficiency (Pellagra)
- Vitamin B9 deficiency (Folate)
- Vitamin B7 deficiency (Biotin)
- Vitamin B12 deficiency
- Vitamin C deficiency (Scurvy)
- Vitamin D deficiency (Rickets)
- Vitamin E deficiency
- Vitamin K deficiency
- Zinc deficiency
Evaluation
Management
- Niacin supplementation.
Disposition
See Also
External Links
References
- Badaway, Abdulla. “Pellagra and Alcoholism: a biochemical perspective.” Alcohol and alcoholism 2014; vol 49, No 3, pages 238-250
- Lopez, Marta, et al. “Pellagra Encephalopathy in the context of alcoholism: review and case report.” Alcohol and alcoholism. Vol 49. No 1. pages 38-41. 2014.