[Brain teasers in pruritus-when laboratory tests will guide you].

Chronic pruritus is a symptom of many systemic diseases. In contrast to dermatological pruritus, there are no primary changes in skin appearance. Establishing the correct diagnosis in these cases can be quite challenging. In some instances, laboratory tests can be helpful. This report highlights the importance of specific and target-orientated laboratory tests in four patients with chronic pruritus due to systemic diseases.