Leiner disease is a clinical phenotype marked by the triad of noncongenital or acquired erythroderma, diarrhea, and failure to thrive. Leiner disease may not represent a distinct clinical entity because infants with the clinical phenotype have eventually been diagnosed with various other conditions, including congenital immunodeficiencies, Netherton syndrome, Omenn syndrome, and eosinophilic gastroenteritis. Affected infants develop an acquired generalized desquamative dermatitis within the first few weeks of life. They also suffer from diarrhea, weight loss, and failure to thrive.