Eczema and Urticaria as Manifestations of Undiagnosed and Rare Diseases.

Eczema and urticaria are common disorders encountered in pediatric patients, but they may occasionally be the presenting complaint in a child with an underlying rare disease. Immunodeficiency syndromes should be suspected when eczema is associated with neonatal onset, recurrent infections, chronic lymphadenopathy, or failure to thrive. Nutritional deficiencies and mycosis fungoides are in the differential diagnosis for a child with a recalcitrant eczematous eruption. Autoinflammatory syndromes should be suspected in a child with chronic urticaria, fever, and other systemic signs of inflammation. Although these disorders are rare, early recognition allows for appropriate treatment and decreased morbidity for the child.