Pellagra: Difference between revisions
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==Background== | ==Background== | ||
Pellagra is the deficiency of Niacin (Vitamin B3). Niacin | *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 absoprtion | ===Conditions that decrease niacin GI absoprtion=== | ||
* | *[[Colitis]] | ||
* | *[[Celiac disease]] | ||
* | *[[Crohn's disease]] | ||
* | *[[Ulcerative colitis]] | ||
* | *[[Cirrhosis]] | ||
* | *[[Weight loss surgery complications|Gastrectomy]] patients | ||
==Clinical Features== | ==Clinical Features== | ||
* Skin photosensitivity and rash. Erythematous and scaly. May be mistaken for sunburn. | [[File:Pellagra2.jpg|thumb|Dermatologic features of pellagra including peeling, redness, scaling, and thickening of sun-exposed areas.]] | ||
**secondary to UV damage and decreased repair | [[File:Casal's_necklace.png|thumb|Casal's Necklace in a case of isoniazid-induced pellagra.]] | ||
[[File:PHIL 3757 lores.jpg|thumb|Boy with classic pellagra rash.]] | |||
''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 and hence the desquamation, keratosis and erythema is most common in sun-exposed skin | |||
**"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. | ||
*GI symptoms | *GI symptoms | ||
**secondary to decreased cell turnover | **secondary to decreased cell turnover | ||
*Neurological symptoms | *Neurological symptoms | ||
**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== | ||
{{Generalized rash DDX}} | |||
{{Vitamin deficiencies DDX}} | |||
== | ==Evaluation== | ||
==Management== | ==Management== | ||
*[[Niacin]] supplementation. | |||
==Disposition== | ==Disposition== | ||
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==References== | ==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. | |||
<references/> | <references/> | ||
[[Category:Dermatology]] | |||
[[Category:FEN]] |
Revision as of 17:47, 10 September 2020
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 and hence the desquamation, keratosis and erythema is most common in sun-exposed skin
- "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.