Itchy skin has many causes, including dryness and allergies, but only rarely does it signal that a person has cancer.
This symptom may occur as a result of complications of the disease, and itchy, flaky skin and rashes are common side effects of some cancer drugs. Most skin cancers, such as malignant melanoma, don’t normally cause itching.
One form of cancer in which itching is a prominent sign is polycythemia vera, one of several blood cancers known as myeloproliferative disorders. People with this disease may experience itchiness particularly after a warm bath or hot shower, but this is only one of many symptoms associated with polycythemia vera. Others are trouble breathing when lying down, dizziness, headache, fatigue, and others.
Scaly skin and red rashes may be an early sign of mycosis fungoides or Sezary Syndrome, which are forms of cutaneous T-cell lymphoma. Mycosis fungoides goes through a series of phases, beginning with red rashes that may last for months or years, followed by the development of bumps or hardened lesions on the skin, and eventually tumors that form on the skin and may be infected.
Pancreatic cancer is another disease where patients may experience itching, but itching in itself is not a sign of pancreatic cancer. Pancreatic cancer patients may experience itching if their tumor blocks the bile duct and causes jaundice, says Robert Mayer, MD, of Dana-Farber’s Gastrointestinal Cancer Treatment Center. When this occurs, chemicals in the bile can leak into the skin and cause itching.
Some cancer treatments may cause itching or rashes over the entire body or in isolated areas. This may be result from a hypersensitivity reaction during chemotherapy infusion. In some cases, itching may be a chronic side effect of treatments, including biologic agents, radiation therapy, and a variety of targeted drugs.