Neonatal citrullinemia associated with cutaneous manifestations and arginine deficiency.

A patient with neonatal citrullinemia (argininosuccinic acid synthetase deficiency), a heritable disorder of the urea cycle, developed a generalized cutaneous eruption at 35 days of age. The skin lesions consisted of erosive, erythematous, scaling patches and plaques. The plasma arginine concentration at that time was low. After treatment with oral arginine supplements, the cutaneous lesions rapidly resolved and the plasma arginine concentration normalized. Histologic features of pretreated lesions included parakeratosis, crust formation, absence of a granular cell layer, pallor of the upper epidermal cells, and a mild, superficial, perivascular, mononuclear-cell infiltrate. Since the patient's skin lesions responded to arginine supplements, and since arginine is a component of keratin, we postulate that the skin lesions are the result of arginine deficiency.