Tracking down the cause of your itch can take time and involve a physical exam and a careful history. If your doctor suspects your itchy skin is the result of an underlying medical condition, he or she may perform tests, including:
- Blood test. A complete blood count can provide evidence of an internal condition causing your itch, such as iron deficiency.
- Tests of thyroid, liver and kidney function. Liver or kidney disorders and thyroid abnormalities, such as hyperthyroidism, may cause itching.
- Chest X-rays. Signs of underlying disease that are associated with itchy skin, such as enlarged lymph nodes, can be seen by using X-rays.