[Pruritus--also a challenge in internal medicine].

Generalized or localized itch without primary skin manifestations may be the presenting symptom of serious internal diseases. Five characteristic cases of pruritus are discussed: Hodgkin's disease, primary sclerosing cholangitis, polycythemia vera, iron deficiency (with pica), and uremia. Other important causes must be considered; all forms of cholestasis, including primary biliary cirrhosis, drug-induced, pregnancy-related, and extrahepatic cholestasis; other hematologic and malignant disorders such as non-Hodgkin's lymphoma, leukemia, multiple myeloma, solid tumors, and myelodysplastic syndromes; metabolic and endocrine diseases, most notably diabetes mellitus, hyperthyroidism, hypothyroidism, and carcinoid syndrome; focal neurologic diseases such as brain tumors, cerebral infarctions and multiple sclerosis; adverse drug reactions without rash; infectious diseases, especially parasitic and HIV infections. A diagnostic laboratory screening for pruritus of undetermined origin is suggested.