When is Itchy Skin a Sign of Cancer?

By Dr. Muzammil Shaikh in Nanavati Max Institute of Cancer Care

Apr 24 , 2023 | 3 min read

Overview

Itchy skin or pruritus is a sensation of discomfort that encourages a person to scratch. There are many reasons behind skin itching, including allergic reactions, dry skin, or underlying health conditions such as diabetes. Sometimes it can be prominent skin cancer symptoms or the result of cancer treatments. Studies have revealed that people with generalised itching are more likely to develop skin cancer than those without itching.

Why does cancer cause itching?

Just like pain receptors causes pain when getting irritated. Similarly, our body contains receptors on nerve endings, which on irritation, cause itching. The irritation can be the result of the following reasons:

Inflammation: Some cancers that involve skin linings can trigger itching in the presence of inflammation. It is seen in cases of skin cancers, breast cancers, and anal or vulvar cancers.
Bile salts: The liver produces bile which is used to digest complex foods. When the tubes that carry bile (bile ducts) block, it results in bile salts buildup under the skin. The buildup results in severe itching. It is also seen in cases of cancers involving the breakdown of blood cells, such as leukaemias and lymphomas.
Chemicals: Sometimes, cancerous cells or our body releases substances in response to tumours that can result in itching. Such substances are cytokines, substance P, and prostaglandins.
Hormonal changes: Fluctuating hormone levels can cause hot flashes followed by sweats leading to itching.

What types of cancer can cause itching?

Skin itching is found in association with the following types of cancers:

Skin cancer: It is identified by changing skin colour at a spot on the body. The most common skin cancer symptom is itchiness.
Lymphoma: The itchiness experienced by a person in T-cell lymphoma and Hodgkin’s lymphoma is due to a chemical released by the immune system in reaction to cancerous lymphoma cells.
Pancreatic cancer: Itchiness is not a direct symptom of pancreatic cancer but results from jaundice developed during it.
Polycythemia vera: It is a type of blood cancer where itchiness might be experienced after a bath or hot shower.
Other cancers: Itchiness is also found in association with the following types of cancer such as bile duct cancer, vulvar cancer, anal cancer, breast cancer, gallbladder cancer, leukaemia, liver cancer, metastatic cancer, including lung cancer and colorectal cancer

Which cancer treatments cause itchiness?

Itchiness during cancer treatment is a sign of an allergic reaction to the therapy or drug. In the following cancer treatment, long-term itching is seen:

Chemotherapy
Radiation therapy
Immunotherapy drugs such as Interleukin-2 and Interferons
Therapies including bortezomib, rituximab, ibrutinib, and brentuximab vedotin
Hormone therapy in breast cancer, including anastrozole, letrozole, tamoxifen, and raloxifene

When does itching mean that skin cancer might be present?

Itching due to cancer or other reasons, most have similar characteristics. Here is the list of characteristics of itching when it is a skin cancer symptom:

Itching occurs in response to water or aquagenic pruritus.
Lack of hives or skin rash.
Yellowish discolouration of the skin.
The itching feels worse on the lower part of the legs and chest.
Burning sensation in some cases.

Cancer-related itching is associated with the following skin conditions:

Erythroderma: Severe red and scaly skin throughout the body
Acanthosis Nigerians: Dark and thickened skin
Dermatomyositis: Rash with muscle weakness
Grover’s disease: Itchy rash on chest
Seborrheic keratosis: Eart-like skin growth

Associated with other symptoms of the body, including weight loss, fever, and night sweats.

Other causes of itchy skin

Besides being a skin cancer symptom, itchy skin can be the result of the following health conditions:

Allergic reactions
Dry skin
Eczema
Insect bites
Bug bites, including lice and ticks

Following underlying health conditions:

Diabetes
Shingles
Liver disease
HIV
Kidney disease
Iron deficiency anaemia
Hyperactive thyroid gland
Stroke
Multiple sclerosis

When to see your doctor?

It is difficult to identify the probable cause of itching. However, there are some clues to differentiate itching due to cancer from itching due to other reasons. If a person is experiencing the following symptoms, they should immediately consult a doctor as it can be skin cancer symptoms:

Itching lasting for more than 48 hours.
Dark-coloured urine
Skin turning yellow
Tendency to scratch the skin until it’s bleeding or open.
Skin rash, which worsens with applications of ointments.
The skin has developed bright red colour, blisters, or crusts.
Skin with pus and unpleasant odour.
Sleeplessness due to itching.
When the person signs of an allergic reaction such as shortness of breath, swelling in the throat and running nose.

Conclusion

Itching can be the result of many potential causes, including skin cancers. It is, therefore, paramount to consult a doctor when a person experiences unusual itching. The doctor will identify the specific case behind it and give them treatment to ease the itch.