HISTORY
A 5-month-old girl with progressively worsening generalized rash of 3 weeks’ duration. No obvious sensitivity, fever, recent infection, medication use, or known contact with irritant.
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Infant born at 39 weeks’ gestation via spontaneous vaginal delivery in whirlpool bath after an uncomplicated pregnancy. Weight 3.22 kg (7.2 lb). Some thin meconium present in amnionic fluid, without any further issues. Breastfeeding appropriately, with regular stool and urine production. Mother had no significant medical history and took no medications. No known family history of lung, endocrine, malabsorption, or dermatological disorders.
The rash first appeared on the bilateral proximal thighs (A). After an initial diagnosis of eczema by the family physician, the mother applied 10% urea(Drug information on urea) cream and used an oat-based baby wash product during weekly bathing. The rash persisted. A dermatologist/allergist who evaluated the infant noted that she had large cheeks and pale skin (B) and suggested a workup for anemia. However, difficulty in achieving venous access impeded efforts to complete this workup. The dermatologist diagnosed the rash as seborrheic dermatitis and prescribed nystatin(Drug information on nystatin) cream. After 2 weeks of treatment, the rash had increased in intensity. Pediatric evaluations during this time showed that the 5-month-old had not met standard growth parameters; her length was 57 cm, and her weight, 4.8 kg (both below the 5th percentile). In addition, the mother reported that the infant’s stools had become increasingly watery and frequent, with a fatty consistency, but had no blood, mucus, or foul odor.
Another dermatologist prescribed 2.5% hydrocortisone(Drug information on hydrocortisone) cream for presumed skin irritation from bathing practices; the rash remained unchanged after 8 days of treatment. During a third dermatology evaluation, zinc deficiency was diagnosed. A zinc-rich diet was recommended pending laboratory evaluation. Persistent failure to meet standard growth parameters instigated further pediatric genetic, neurological, ophthalmological, and gastroenterological consultations. A brain MRI scan was normal. Results of genetic testing for Prader-Willi syndrome were negative. Stool studies were ordered pending GI consultation.
PHYSICAL EXAMINATION
Mildly lethargic, hypotonic, pale infant with plaques of desquamating, erythematous rash on the lower legs, perineum, antecubital areas, scalp, and bilateral angles of the mouth (C). She had facial and pedal edema with pitting on pressure. Scalp had universal, spotty loss of reddish brown hair and sparse regrowth of blond hair.
LABORATORY FINDINGS
White blood cell count, 10,800/μL; red blood cell count, 3.0 x 106/μL; hemoglobin, 7.6 g/dL; hematocrit, 24.3%; platelet count, 264,000/μL. Basic metabolic panel, creatine kinase, lactate dehydrogenase, uric acid, and bilirubin indices, all normal. Aspartate aminotransferase, 111 U/L; alanine aminotransferase, 90 U/L; albumin, 23.1 g/L; transferrin, 0.64 g/L (normal, 2.35 to 4.03 g/L); transferrin saturation, 91%; ferritin, 644 μg/L; vitamin A, 1.0 μmol/L; vitamin E(Drug information on vitamin e), 9.3 μmol/L; vitamin B12, 1075 pmol/L; folic acid(Drug information on folic acid), 21 nmol/L; vitamin D3, 62.9 ng/mL. Stool negative for blood and pancreatic elastase. Urinalysis showed moderate ketonuria; evaluation of serum amino acids showed nonspecific changes. Findings from coagulation studies were normal. Sweat chloride testing revealed moderate elevation of sodium and chloride levels (chloride, 69 mmol/L; sodium, 92 mmol/L).
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