RESUMEN
BACKGROUND: Celiac disease (CD) is a complex autoimmune disorder that can lead to an inflammatory small intestinal villous atrophy and malabsorption. Hartnup disease is an autosomal recessive disorder caused by increased urinary excretion of neutral amino acids. Co-occurrence of Hartnup disease and CD is extremely rare with only a single case reported. CASE PRESENTATION: We report a 3-year girl with chronic diarrhea, Hypoalbuminemia and exfoliative erythema. She was diagnosed with celiac disease, which did not improve on gluten free diet. Hartnup disease was suspected and was confirmed by neutral aminoaciduria. Niacin was started and followed by dramatic improvement. CONCLUSION: Presence of Celiac and Hartnup disease in single individual is very rare. Complete nutritional assessment of refractory celiac patient can reveal underlying nutritional deficiency.