Hartnup Disease Differential Diagnoses

Updated: Nov 12, 2021
  • Author: Lidija Kandolf Sekulovic, MD, PhD; Chief Editor: William D James, MD  more...
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Diagnostic Considerations

Regarding rash, consider the following:

  • Infantile atopic eczema
  • Seborrheic eczema
  • Nutritional pellagra (Misdiagnosis can be prevented by performing urine chromatography.)
  • Congenital poikilodermas with photosensitivity (eg, Cockayne syndrome)
  • Malar rash of lupus erythematosus
  • Carcinoid syndrome (may lead to disturbance of tryptophan metabolism and pellagralike rash)
  • Indicanuria in inborn errors of amino acid metabolism (eg, phenylketonuria, blue diaper syndrome)

For the central nervous system, consider the following:

  • Ataxia-telangiectasia (can cause diagnostic difficulties, especially in patients with mild skin involvement)
  • Systemic lupus erythematosus (can be confused if photosensitivity with neuropsychiatric symptoms is present)
  • Other ataxias with biochemical and genetic defects

Differential Diagnoses