- Only rarely does itching signal that a person has cancer.
- Some cancer treatments themselves may cause itching or rashes.
Got an itch that just won’t go away? Also known as pruritus (proo-rai-tuhs), itchy skin can have a wide variety of causes, including seasonal allergies and dry skin; various skin conditions, such as eczema; and even certain detergents and lotions.
The good news is that itchy skin is typically not a sign of 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 don’t normally cause itching.
Anyone with a prolonged, unexplainable itch should consult either their primary care physician or a dermatologist.
Which cancers can be associated with itching?
The cancers that are most commonly associated with itching are lymphoma, polycythemia vera (PV), certain gastrointestinal cancers, and melanoma.
Itching can be common in people with Hodgkin lymphoma as well as other lymphoid malignancies, such as chronic lymphocytic leukemia (CLL). According to Jennifer Crombie, MD, an oncologist at the Center for Hematologic Oncology at Dana-Farber/Brigham and Women’s Cancer Center (DF/BWCC), itchiness can be seen in up to 20% of diagnosed cases of Hodgkin lymphoma.
In some instances, itchiness can be severe and localized throughout the body rather than in a single spot, and can occur without an associated rash. The symptoms of itchiness can also precede the diagnosis of cancer.
While lotions or antihistamines may help, patients often require treatment of their lymphoma to improve their symptoms. While it is still unclear as to why some patients experience itchiness, it is believed the cancer may trigger the release of substances, known as cytokines, in the body that cause the symptom.
People who experience scaly skin and red rashes may be exhibiting an early sign of mycosis fungoides or Sezary syndrome, which are forms of cutaneous T-cell lymphoma (CTCL). CTCL is a rare form of non-Hodgkin lymphoma that develops in abnormal T cells, white blood cells that are used to fight infections. CTCL typically develops very slowly and, unlike cases of Hodgkin lymphoma, itchiness may be contained to the affected skin.
It is important to remember that itchiness is not a criterion for lymphoma staging and does not indicate a more or less favorable diagnosis. Once a patient begins treatment, the itchiness should go away.
“While rare, itchiness can be associated with malignancies,” says Crombie. “For this reason, it’s something people should be aware of. If you’re experiencing severe or prolonged itchiness with no clear cause, you should see a doctor.”
Polycythemia vera (PV)
PV is a form of blood cancer in which the bone marrow produces an abnormal amount of red blood cells.
PV is categorized as a myeloproliferative disorder — an umbrella term used to describe a number of blood cancers in which the bone marrow makes too many abnormal red blood cells, white blood cells, or platelets.
People with this disease often report experiencing itchiness following a warm bath or hot shower. Other symptoms associated with PV include:
- Trouble breathing when lying down
Certain gastrointestinal cancers — cancers that affect the digestive system — may also lead to itchiness. However, itching that is not accompanied by other symptoms is not considered indicative of gastrointestinal cancer.
In the cases of these cancers, itchiness is caused by obstructive jaundice. Jaundice is a yellowing of the skin, and this specific type of jaundice occurs when the bile ducts is either blocked or narrowed. This blockage, which can be a result of a tumor, prevents the normal drainage of the fluid from the bloodstream into the intestines.
The types of gastrointestinal cancer that are most commonly associated with obstructive jaundice include pancreatic cancer, liver cancer, and gallbladder cancer.
Melanoma is a type of cancer that originates in the melanocytes, cells that make the pigment melanin. An itchy mole is considered a warning sign for melanoma and should be examined by a dermatologist. A person with melanoma won’t experience itching throughout the body; instead, it will be contained to the mole itself, and surgically removing it will relieve any itchiness.
If a biopsy confirms the mole is melanoma, the fact it was itchy can be indicative of a positive outlook. Itchiness is often a sign that the immune system has ramped up in order to attack the cancer cells, according to Elizabeth Buchbinder, MD, an oncologist at the Center for Melanoma Oncology at DF/BWCC.
Can cancer treatments cause itching?
Some cancer treatments may lead to itching or rashes, which can occur both over the entire body or in isolated areas. Chemotherapy, radiation therapy, and immunotherapy have all been known to cause itchiness.
For a patient undergoing chemotherapy, itching could be an early sign that they are allergic to the drugs. In the case of radiation therapy, itching can indicate damage to the healthy cells. For patients undergoing immunotherapy, rashes and itchiness can be signs of inflammation in the skin.
In some instances, itching may be a chronic side effect of certain treatments, including:
- Biologic agents
- Radiation therapy
- A variety of targeted drugs
If you’re experiencing itchiness, make sure to tell your oncologist as they will be able prescribe something to help.