What is the diagnosis and treatment for a 15-year-old girl with chronic loose, greasy, and foul-smelling stools, facial erythema (redness), puffiness, and hyperpigmentation (skin darkening) around the chin?

Diagnosis: Acrodermatitis Enteropathica-like Presentation Secondary to Malabsorption (Most Likely Celiac Disease or Cystic Fibrosis)

This 15-year-old girl with chronic greasy, foul-smelling stools (steatorrhea) combined with facial erythema, puffiness, and perioral hyperpigmentation most likely has a malabsorption syndrome causing zinc deficiency, with celiac disease being the most probable diagnosis given her age and presentation. 1

Clinical Reasoning

The combination of steatorrhea and characteristic dermatologic findings points to malabsorption with nutritional deficiency:

• Steatorrhea characteristics: Bulky, malodorous, pale/greasy stools over one year indicate fat malabsorption from small bowel pathology 1
• Dermatologic manifestations: Facial erythema with puffiness and hyperpigmentation around the chin strongly suggests zinc deficiency (acrodermatitis enteropathica-like presentation), which occurs with malabsorption syndromes 2
• Age consideration: In a 15-year-old, celiac disease is the most common small bowel enteropathy in Western populations 1, 3

Differential Diagnosis Priority

Primary Considerations:

1. Celiac Disease (most likely)

   • Most common small bowel enteropathy causing malabsorption 1
   • Can present with nonclassic symptoms including dermatologic manifestations from nutritional deficiencies 3, 2
   • Zinc deficiency from malabsorption causes perioral dermatitis and facial changes 2

2. Cystic Fibrosis

   • Pancreatic insufficiency causes steatorrhea with loose, foul-smelling fatty stools 1
   • Affects >80% of CF patients at diagnosis 1
   • Nutritional malabsorption leads to dermatologic manifestations including acrodermatitis enteropathica-like changes 2, 4

3. Chronic Pancreatitis (less likely at this age)

   • Causes pancreatic enzyme deficiency and fat malabsorption 1

Diagnostic Workup

First-Line Investigations (Primary Care/Initial Assessment):

• Serologic testing for celiac disease: IgA tissue transglutaminase (IgA-TG2) is the recommended initial screening test 1, 3
• Complete blood count: Check for anemia (iron, B12, folate deficiency from malabsorption) 1
• Serum albumin and liver function tests: Assess nutritional status and malabsorption 1
• Serum zinc level: Confirm zinc deficiency causing dermatologic manifestations 2
• Fat-soluble vitamin levels (A, D, E, K): Document deficiencies from fat malabsorption 1, 2

Second-Line Investigations (If Initial Tests Suggest Malabsorption):

• Esophagogastroduodenoscopy with small bowel biopsy: Confirm celiac disease diagnosis (villous atrophy, crypt hyperplasia, increased intraepithelial lymphocytes) 1, 3
• Fecal elastase-1: If pancreatic insufficiency suspected (CF or chronic pancreatitis) 1, 5
• Sweat chloride test: If cystic fibrosis suspected based on clinical presentation 1, 4
• Genetic testing for CFTR mutations: If CF is being considered 1, 4

Important Caveats:

• Check IgA levels concurrently with IgA-TG2, as 2% of celiac patients have IgA deficiency; if deficient, use IgG-based tests (IgG-DGP or IgG-TG2) 1
• Patient must be on gluten-containing diet during serologic testing and biopsy for accurate celiac disease diagnosis 1, 3
• Biopsy remains gold standard for celiac disease diagnosis in adults despite high antibody titers 1

Treatment Approach

If Celiac Disease Confirmed:

Lifelong strict gluten-free diet is the primary and only treatment 1, 3

• Nutritional supplementation: Immediate zinc supplementation for dermatologic manifestations, plus iron, folate, B12, and fat-soluble vitamins as needed 3, 2
• Dietitian referral: Education on gluten avoidance, hidden sources, cross-contamination, and balanced nutrition 3
• Monitor response: Weight gain, resolution of steatorrhea, and improvement in dermatologic findings expected within weeks to months 1, 3

If Cystic Fibrosis Confirmed:

Pancreatic enzyme replacement therapy with high-protein, high-calorie diet 1, 4

• Pancreatic enzymes: Dose adjusted to control steatorrhea 1, 5
• Fat-soluble vitamin supplementation: A, D, E, K in higher doses 1
• Zinc supplementation: For dermatologic manifestations 2
• Multidisciplinary CF care: Pulmonary management, nutritional support, infection prevention 1

If Diagnosis Remains Unclear After Initial Workup:

• Therapeutic trial: If celiac serology positive but biopsy delayed, gluten-free diet trial with zinc supplementation can be diagnostic if symptoms resolve 3
• Reassess for coexisting conditions: CF patients can have concurrent celiac disease (1.4% incidence); screen for CD if inadequate response to pancreatic enzyme replacement 4

Red Flags Requiring Urgent Evaluation

• Significant weight loss: Suggests severe malabsorption requiring aggressive nutritional intervention 1
• Nocturnal or continuous diarrhea: More likely organic disease than functional disorder 1
• Duration >1 year with progressive symptoms: Warrants comprehensive malabsorption workup 1