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Drugs and other conditions causing pellagra Or pellagra like dermatitis

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pellagra AND dermatitis

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pellagra causes drugs carcinoid Hartnup disease clinical reference

Quick answer

Pellagra is due to niacin (vitamin B3) or tryptophan deficiency. Its classic features are the “3 Ds”: photosensitive dermatitis, diarrhea, and dementia. The dermatitis can be sharply demarcated over sun-exposed sites, including the neck (Casal necklace), dorsal hands and forearms.

Drugs that can cause pellagra or pellagra-like dermatitis

  • Isoniazid: most important drug cause. It interferes with niacin-related metabolism and pyridoxine function.
  • Ethionamide and prothionamide
  • Pyrazinamide
  • Azathioprine and 6-mercaptopurine
  • 5-fluorouracil
  • Anticonvulsants: especially phenytoin/hydantoins, phenobarbital, and carbamazepine
  • Chloramphenicol: reported to interfere with tryptophan-niacin conversion
  • Levodopa: reported association, particularly with poor nutrition or long-term treatment

Conditions causing secondary pellagra

Reduced intake or malnutrition

  • Chronic alcohol use disorder
  • Starvation, famine, poverty
  • Diet predominantly based on untreated maize/corn
  • Severe dietary restriction, anorexia nervosa, food-faddism
  • Protein-energy malnutrition

Malabsorption or gastrointestinal disease

  • Crohn disease and other inflammatory bowel diseases
  • Celiac disease
  • Chronic diarrhea or malabsorption syndromes
  • Whipple disease
  • After major gastrointestinal surgery, including gastric bypass/bariatric surgery

Altered tryptophan metabolism or loss

  • Carcinoid syndrome/tumors: tryptophan is diverted to serotonin synthesis
  • Hartnup disease: inherited defect causing impaired intestinal absorption and renal reabsorption of neutral amino acids, including tryptophan
  • Severe chronic illness, malignancy, or HIV/AIDS may contribute through malnutrition and impaired absorption/metabolism

Important distinction

“Pellagra-like dermatitis” may also be considered in the differential of a photosensitive eruption. Mimics include:
  • Systemic lupus erythematosus
  • Porphyrias
  • Drug-induced photosensitivity
  • Other nutritional deficiencies and malabsorption states
The medication list and underlying causes above are supported by Andrews’ Diseases of the Skin, niacin-deficiency section, and the DermNet pellagra review.

Angiofibroma seen in what all condition

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angiofibroma AND syndrome

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angiofibroma associated conditions tuberous sclerosis multiple endocrine neoplasia clinical

Angiofibromas are seen mainly in these genetic conditions:
  1. Tuberous sclerosis complex (TSC)
    • Classic association.
    • Multiple facial angiofibromas over the nose, cheeks, and nasolabial folds.
    • Also called adenoma sebaceum, Pringle tumors.
    • Periungual angiofibromas are called Koenen tumors.
    • Three or more facial angiofibromas is a major diagnostic feature of TSC.
  2. Multiple endocrine neoplasia type 1 (MEN1)
    • May show multiple facial angiofibromas, often with collagenomas and lipomas.
    • Usually develop later than those in TSC.
  3. Birt-Hogg-Dubé syndrome
    • Facial angiofibromas may occur, though the more characteristic lesions are fibrofolliculomas and trichodiscomas.
    • Think of associated renal tumors and spontaneous pneumothorax.
Also, an isolated sporadic angiofibroma is common and does not necessarily imply a syndrome.
Do not confuse cutaneous facial angiofibromas with juvenile nasopharyngeal angiofibroma, a separate highly vascular tumor that classically occurs in adolescent boys. Cummings Otolaryngology, Angiofibroma section.
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