Pellagra: Difference between revisions

(18 intermediate revisions by 6 users not shown)
Line 1: Line 1:
==Background==
==Background==
Pellagra is the deficiency of Niacin (Vitamin B3).  Niacin deficiency classically causes the "3 D's": Dermatitis, Diarrhea and Dementia."  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, thereby causing the "3 D's" mentioned above.
*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.


Niacin is either consumed in the diet or converted from tryptophan by the hepatic kynurenine pathway in the liver.  Drugs that inhibit the production of niacin via this pathway can also result in pellagra.  Such drugs include the following:
===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 absoprtion from the GI tract can also lead to pellagra and include the following:
===Conditions that decrease niacin GI absoprtion===
**Colitis
*[[Colitis]]
**Celiac disease
*[[Celiac disease]]
**Crohn's disease
*[[Crohn's disease]]
**Ulcerative colitis
*[[Ulcerative colitis]]
**Cirrhosis
*[[Cirrhosis]]
**Gastrectomy patients
*[[Weight loss surgery complications|Gastrectomy]] patients
 
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.


==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.   
<gallery>
Casal's_necklace.png|Casal's Necklace in a case of isoniazid-induced pellagra.
</gallery>
*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}}


==Diagnosis==
==Evaluation==


==Management==
==Management==
*[[Niacin]] supplementation.


==Disposition==
==Disposition==
Line 48: Line 55:


==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

Conditions that decrease niacin GI absoprtion

Clinical Features

Dermatologic features of pellagra including peeling, redness, scaling, and thickening of sun-exposed areas.
Casal's Necklace in a case of isoniazid-induced pellagra.
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.
  • GI symptoms
    • secondary to decreased cell turnover
  • Neurological symptoms
  • Niacin deficiency is often associated with chronic alcohol use secondary to nutritional deficiency and malabsorption.

Differential Diagnosis

Other Rash

Vitamin deficiencies

Evaluation

Management

Disposition

See Also

External Links

References

  1. Badaway, Abdulla. “Pellagra and Alcoholism: a biochemical perspective.” Alcohol and alcoholism 2014; vol 49, No 3, pages 238-250
  2. 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.