Definition

1. Noun:
   • A nutritional deficiency disease: "Saint Ignatius' itch" is a historical term for a disease caused by a severe deficiency of niacin (vitamin B3) or its precursor, tryptophan. It is characterized by a combination of symptoms including skin inflammation, digestive issues, and neurological or mental disturbances.

Usage Examples

• Noun:
  • The physician diagnosed the sailor's condition as Saint Ignatius' itch, a result of prolonged malnutrition.
  • Before the discovery of vitamins, Saint Ignatius' itch was a common and debilitating ailment on long sea voyages.

Advanced Usage

• Historical/Medical Context: The term "Saint Ignatius' itch" is largely archaic and historical. It is synonymous with the disease now medically known as pellagra. Its usage today is primarily found in historical texts or discussions about the history of medicine and nutrition.

Variants and Related Words

• Pellagra (n): The modern medical term for the disease historically called Saint Ignatius' itch.
  • Pellagra is still found in regions with chronic food insecurity.
• Niacin deficiency (n): The specific nutritional cause of the condition.
  • The symptoms were consistent with severe niacin deficiency.

Synonyms

• Pellagra: The direct modern synonym.
• Malnutrition-related dermatitis: A descriptive term for one of its key symptoms.

Notes on the Term

• Etymology: The name "Saint Ignatius' itch" is an example of an archaic medical term, likely originating from an association with symptoms (severe itching, or "itch") and possibly a historical figure or place (Saint Ignatius). It is important to note that this term is not used in contemporary medical practice.
• Key Characteristics: The definition highlights the classic "three Ds" often associated with advanced pellagra: Dermatitis, Diarrhea, and Dementia.

Noun

1. a disease caused by deficiency of niacin or tryptophan (or by a defect in the metabolic conversion of tryptophan to niacin); characterized by gastrointestinal disturbances and erythema and nervous or mental disorders; may be caused by malnutrition or alcoholism or other nutritional impairments