Itch: a symptom of occult disease

Pruritus, (the Latin word for itch), is defined as the 'desire to scratch'. It is a distressing, subjective symptom that may interfere significantly with the quality of a patient's life.

This article summarises the systemic causes of pruritus, describes the assessment of a patient presenting with itch without dermatological cause, and discusses the management of itch in patients with cancer.

Patients with pruritus that does not respond to conservative therapy should be evaluated for underlying systemic disease. Causes of systemic pruritus include cholestasis, thyroid disease, polycythaemia rubra vera, uraemia, Hodgkin disease, and HIV. A thorough history and a complete physical examination are central to the evaluation of pruritus. In the absence of skin lesions, diagnostic testing is directed by the clinical evaluation and may include a complete blood count, liver function tests, serum creatinine, blood urea nitrogen levels, measurement of thyroid stimulating hormone, and chest X-ray. Removal of the causative agent and appropriate investigation and treatment of the underlying disease are essential first line measures in the treatment of pruritus.