Your skin can itch for many reasons, such as allergies, insect bites and dry skin. The itch, called pruritus, will usually go away once you treat what’s causing it. But sometimes an itch can be chronic, meaning it lasts six weeks or longer. This is known as chronic pruritus.  

In rare cases, chronic pruritus can be a sign of cancer. Here, I’ll explain what types of cancers may cause itchy skin, what the itch feels like and when you should see a doctor.

What types of cancer can cause itchy skin?

Itching can be a sign of several types of blood cancers.

Lymphoma

• Cutaneous T cell lymphoma is a skin lymphoma that starts in the T lymphocytes.
• Hodgkin lymphoma and non-Hodgkin lymphoma both start in the lymphatic system.

Leukemia

• Acute lymphocytic leukemia is a rare, aggressive type of blood cancer that starts in the bone marrow.
• Chronic lymphocytic leukemia and chronic myeloid leukemia are slow-growing types of blood cancer that mostly affect adults over age 55.
• Polycythemia vera is a chronic blood disorder in which the bone marrow produces too many red blood cells. People with polycythemia vera who experience itching have a higher chance of the disease developing into myelofibrosis and acute myeloid leukemia.
• Myelodysplastic syndrome is a group of diseases in which the bone marrow doesn’t make enough healthy blood cells. Some cases develop into acute myeloid leukemia.

Itching can also be a sign of the following cancers:

• Liver cancer
• Bile duct cancer
• Non-small cell lung cancer
• Metastatic stomach cancer
• Pancreatic cancer
• Melanoma: Itching has been reported in 22% of primary melanoma skin lesions.
• Basal cell carcinoma
• Squamous cell carcinoma

Where on the body does the itching occur?

Itching can occur anywhere on the body, including the scalp and genitalia. The most common sites are the lower legs and the trunk – that is, your chest, abdomen, pelvis and back.

How would you describe an itch that might indicate cancer?

There aren’t specific characteristics to look for. What I mean is the itch can be:

• Localized (affecting one area of the body) or generalized (affecting the entire body)
• Constant or intermittent
• Mild to severe

Pruritus may be an associated symptom of cancer. That means it is often an additional symptom of the cancer itself. It’s not necessarily a predictor of cancer. So, if you have itchy skin, it doesn’t mean you will develop cancer.

Itching associated with pancreatic cancer

Itching can happen when pancreatic cancer causes a blockage in the bile duct, which can also lead to jaundice. In these cases, itching tends to be generalized. But I have seen pancreatic cancer patients with intense itching only on their trunk area, or/and only on the arms and legs. 

Aquagenic itch can be a sign of certain cancers

Aquagenic itch describes an itch that develops minutes after contact with water of any temperature with no visible skin rash. Aquagenic itch is commonly seen in people with polycythemia vera. Some people who have aquagenic itch develop cutaneous T cell lymphoma or myelodysplastic syndrome several years later.

How we classify pruritus and cancer

We divide cancer patients with pruritus into three categories:

• Patients who experienced itching before being diagnosed with cancer: A cancer diagnosis may come months to years after the itching begins.
• Patients who have an existing cancer and experience itching
• Patients who have itching indirectly related to cancer: This is usually due to the growth of a tumor affecting internal organs, such as invasive liver tumors.

Cancer treatment can cause itchy skin

Sometimes, cancer treatment can cause rashes and itchy skin. Chemotherapy, opioids, aspirin and antibiotics may cause itching. 

What other conditions can cause itchy skin?

Chronic pruritus can be caused by:

• Diabetes
• Chronic kidney failure
• Liver disease
• HIV infection
• Allergic reactions to food, medicine and insect bites
• Thyroid disorders
• Multiple sclerosis
• Anxiety
• Obsessive-compulsive disorder
• Depression
• Pregnancy

Remember: there are many reasons your skin may itch. Most of the time, it is not because of cancer.

When should you see a doctor for itchy skin?

See a doctor if you have itchy skin that:

• is all over the body, especially during pregnancy,
• starts suddenly,
• lasts for several weeks or longer,
• does not improve with moisturizer use,
• is persistent in the same spot,
• disrupts your sleep or distracts from your daily routine and/or
• is associated with other symptoms, such as weight loss, fever, night sweats, loss of appetite, jaundice, fatigue, cough or visible lumps.

If your doctor cannot find the reason for the itch, they may do a workup to check for other possible causes, including cancer. This workup includes a comprehensive review of your medical history and a physical examination, with particular attention to the lymph nodes. Your doctor will test your complete blood count, liver function, kidney function and thyroid function.

What else should readers know about itchy skin and cancer?

Itchy skin can be frustrating, especially if you don’t know what’s causing it. Itching can be a sign of internal disease, including cancer. We know that patients with certain cancers, namely lymphomas and leukemias, often have associated pruritus, but we have limited data indicating that itchy skin is a predictor of cancer. So, itchy skin alone does not mean you will get cancer.

See a doctor if you have persistent itchy skin and you develop other concerning symptoms. They can figure out what’s causing the symptoms and get you the proper treatment. 

Ana Ciurea, M.D., is a dermatologist at MD Anderson.

Request an appointment at MD Anderson online or call 1-877-632-6789.