Pediatric Pellagra Workup

Updated: Oct 04, 2018
  • Author: Simon S Rabinowitz, MD, PhD, FAAP; Chief Editor: Jatinder Bhatia, MBBS, FAAP  more...
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Laboratory Studies

Therapeutic response to niacin in a patient with the typical symptoms and signs of pellagra establishes the diagnosis.

Low serum niacin, tryptophan, NAD levels, and NADP levels were thought to reflect niacin deficiency and confirm the diagnosis of pellagra.

However, high-pressure liquid chromatography (HPLC) of urinary metabolites of niacin were shown to be a more sensitive investigation to identify pellagra in a cohort known to have the condition compared with measuring blood NAD and NADP levels. Concentrations in spot urine samples of 1-methyl-2-pyridone-5-carboxamide (2-PYR) and 1-methylnicotinamide (1-MN) were reported to be 91% sensitive and 72% specific in estimating niacin deficiency. [20]

While the above-mentioned assays are usually used during suspicion of pellagra, they are actually indirect tests for the dietary intake of niacin and tryptophan. If the deficiencies are short-lived, then they may not necessarily reflect clinical pellagra.


Histologic Findings

Histologically, the acute stage of dermatitis may show a variety of changes, including infiltration of the epidermis with neutrophils, intracellular edema, and intra- or subepidermal vesicle formation

secondary to spongiosis or vacuolar degeneration of the basal layer. Older lesions may present with hyperkeratosis, parakeratosis, and variable acanthosis, with increased basal layer melanin. [13]