A skin rash can occur for many reasons. It is a generic term that people use to describe any change in the skin, such as from infectious disease or an allergic reaction. On very rare occasions, a rash can be a symptom of cancer.
Knowing the difference can help a person seek the necessary help or avoid anxiety about a noncancerous rash.
In this article, we explain how to recognize potentially cancerous rashes. We also cover the different types of cancer that can cause a rash.
It is easy to confuse some noncancerous rashes for a sign of cancer.
For example, people with psoriasis will often experience persistent, scaly, red or pink plaques of skin that may sometimes itch.
The skin might also crack, which can cause further discomfort. Some people may find that this cracked skin occasionally bleeds, especially after itching.
A skin specialist, or dermatologist, can usually identify skin cancer rashes as distinct from those that are typical of psoriasis. Some people, however, may worry about skin cancer when they see a rash.
This may be because certain skin cancers frequently present with certain similar features, such as pink and red discoloration or small areas of bleeding.
It is important to remember that skin cancers are more likely to present as an isolated lesion than several lesions.
Psoriasis, on the other hand, usually presents with several lesions. Also, skin cancer lesions may not respond to typical treatments for psoriasis.
Dermatologists identify skin cancer as a pimple or a scab that does not heal and grows with time. They may recognize melanoma in the form of a new or changing mole.
Moles that indicate melanoma look different to other moles on the body. For example, they may:
- have irregular borders
- lack symmetry
- present with a variety of colors
- be larger than 6 millimeters across
- change with time
Skin cancer rashes will typically not resolve on their own, unlike those of other skin conditions. As the cancer grows, the size and shape of the lesion or rash will usually change. It may grow into deeper layers of skin and change shape.
Skin cancer may develop in visible locations on the skin, so identifying these early on is often easier than with other types of cancer. Doing so also makes successful treatment more likely.
However, skin cancer can also develop in areas that are not easily visible, such as the back, scalp, and bottom of the feet.
Anyone who is uncertain about their skin symptoms should seek immediate consultation with a doctor or dermatologist.
Not all skin cancers will present with a rash. For example, melanomas — which develop from the melanocyte cells that provide pigment to the skin — often resemble misshapen moles.
Melanomas are one of the most life threatening forms of skin cancer, so surveillance for an early lesion is essential for prompt treatment and a good prognosis.
There are a variety of cancerous and precancerous rashes. Precancerous rashes may evolve into cancerous ones over time, and early diagnosis and treatment are vital in every case.
Below, we list the types of skin cancer that tend to cause a rash, a lesion, or other skin symptoms:
Actinic keratosis, or solar keratosis, occurs after excessive sun exposure on a particular area of the body. People with an actinic keratosis may develop a small, red, scaly patch on the skin. The patch usually does not cause symptoms.
Actinic keratosis most commonly occurs on exposed areas of the body, such as the hands, head, or neck.
These patches are precancerous lesions. Over time, there is a slight risk that they will develop into a type of cancer called squamous cell carcinoma (SCC). It can be difficult for doctors to determine whether or not an actinic keratosis patch will change over time and become cancerous.
Even though most cases of actinic keratosis do not turn into cancer, doctors still recommend early treatment and attending regular checkups to prevent the development of cancer.
Here, learn more about actinic keratosis.
Basal cell carcinomas
Basal cell carcinoma (BCC) is a type of cancer that often starts as a pearly papule or bump, often on the nose or another area of the face.
The papule may then grow and become shinier. It may start to bleed in the center, where an indentation may form.
In other areas of the body, BCC may appear as a small, scaly, pink patch or a pigmented, shiny bump. It may even present as an irregular scar.
As the cancer progresses, the area may become crusty and start to bleed or ooze.
Actinic cheilitis, also known as farmer’s lip, is a precancerous rash that usually develops on the lips. The condition produces scaly patches or rough lips.
This type of rash often develops after years of exposure to ultraviolet rays. Very often, this occurs due to a large amount of time spent doing outdoor workTrusted Source, such as agricultural work, marine work, or jobs at a high altitude.
Without treatment, actinic cheilitis may develop into SCC.
SCC is most likely to appear as a very scaly, crusted, pink papule that bleeds easily and grows with time.