From healthcentral.com
The conditions are quite different, but in some cases, they may look similar. Here’s how to distinguish between them
Key Takeaways
- Psoriasis and some skin cancers can both look red and scaly, so appearances can be misleading.
- Psoriasis plaques are usually broad and may cover large areas, while skin cancers are more often isolated bumps.
- Psoriasis can spread quickly over months, while many skin cancers stay small and grow slowly.
- Dermatologists often diagnose by exam, and a biopsy can clearly distinguish psoriasis from skin cancer.
- Early evaluation and treatment matter, because untreated psoriasis can cause infection and distress, and skin cancer can spread.
Discovering a new rash or growth on your skin can be nerve-wracking. The spectrum of possible answers to the question “What is it?” ranges from absolutely nothing to an inflammatory condition like psoriasis, to skin cancer. And after Googling it, you might think it’s all three. So, how can you figure it out? When it comes to psoriasis and skin cancer, while the two diseases are very different, to the untrained eye, appearances may look similar. Here’s what you need to know about the similarities and differences between psoriasis and skin cancer.
Types of Psoriasis and Skin Cancer
Psoriasis and skin cancer both have multiple variants that present differently, which can complicate their diagnosis.
Types of Psoriasis
Plaque Psoriasis
Guttate Psoriasis
Pustular Psoriasis
Inverse Psoriasis
Erythrodermic Psoriasis
Types of Skin Cancer
Basal Cell Carcinoma (BCC)
Squamous Cell Carcinoma (SCC)
Dermatofibrosarcoma protuberans (DFSP)
Merkel cell carcinoma
Sebaceous carcinoma
In most cases, psoriasis and skin cancer look distinct, says Lisa Rhodes, M.D., a dermatologist at Westlake Dermatology in Austin, TX. For example, melanoma appears as an abnormal mole; strikingly different from any type of psoriasis. However, in some instances, psoriasis and skin cancer can have similar symptoms. “Psoriasis is a red, scaly plaque of skin,” explains Dr. Rhodes. “Basal cell carcinoma and squamous cell carcinoma can also be red and scaly.” This raised, red, and scaly characteristic is the most correlated symptom between the two conditions. Plaque psoriasis and squamous cell carcinoma are most likely to present in this way.
According to the AAD, precancerous skin growths called actinic keratoses (AKs) look like dry, scaly patches or spots on the skin. They’re caused by sun exposure and can develop into SCC over time, per the AAD.
When trying to discern skin cancer from psoriasis, a few key traits can tip you off:
Shape: “Typically plaque psoriasis is broader than it is raised,” Dr. Hwang notes. “Skin cancers generally look more like bumps, or little hills.”
Surface Area: While psoriasis can be limited to one or two areas on the body, it generally spans large areas, whereas skin cancer is limited to one isolated area or lesion, Dr. Hwang notes. “The broad nature and coverage of psoriasis would very rarely happen in cancer.”
Speed of Growth: “Skin cancers tend to be small and grow slowly,” Dr. Hwang adds. “Psoriasis can develop quickly over a few months and cover a whole region.”
Both conditions are typically diagnosed with a physical exam—a dermatologist will look at your skin with a dermatoscope, a tool that uses magnification and light—and a medical history. Your clinician will ask about your symptoms, overall health, family history, and recent life events and stressors that may play a role in either psoriasis or skin cancer, explains Samuel Hwang, M.D., Ph.D., professor and chair of dermatology at UC Davis Health in Sacramento, CA.
More often than not, a licensed dermatologist can tell just by examining your skin whether you’re dealing with psoriasis or skin cancer, Dr. Hwang says. They are trained to spot different types of skin cancer and use the ABCDEs of melanoma to diagnose a skin spot—asymmetry, border, colour, diameter, evolving.
If the cause of your skin growth or rash isn’t apparent, your doctor will take a sample of the skin and send it to a lab for testing, called a biopsy. “Psoriasis and skin cancer look different on a biopsy,” Dr. Hwang explains. This will allow your doctor to make an accurate diagnosis and ensure that you get the proper care.
How Psoriasis and Skin Cancer Are Treated
The importance of a correct diagnosis can’t be overstated, in large part because the treatments for psoriasis or skin cancer are drastically different. Whatever you’re dealing with, you’ll want to receive treatment sooner rather than later to improve symptoms and avoid complications.
Psoriasis Treatment
If you do have psoriasis, the treatment option your doctor chooses will depend on the severity, type, how your body responds to certain medications, as well as your lifestyle. Psoriasis is a chronic condition, so while treatment can keep symptoms at bay for long periods of time, it’s normal to still experience flare-ups from time to time, especially when you encounter triggers like stress.
According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), psoriasis treatments include:
Topical medications including corticosteroids, vitamin D-based therapies, retinoids, and coal tar
Oral retinoids
Phototherapy
Oral immunosuppressants including methotrexate and phosphodiesterase 4 (PDE4) inhibitors
Injectable immunomodulating medications called biologics
Skin Cancer Treatment
Skin cancer treatment is also tailored to the type of cancer you have and the stage at diagnosis—in other words, whether it’s in an early stage and confined to the top layer of the skin, or at a later stage and already spread to other areas. In general, skin cancer treatment may consist of the following, per the National Cancer Institute:
Surgery, of which there are many different types depending on depth and size
Radiation therapy
Chemotherapy
Photodynamic therapy, which uses a drug that concentrates in cancer cells and is activated by a laser light
Immunotherapy, including drugs called PD-1 inhibitors (which reprogram the body’s immune system to fight the cancer), topical imiquimod therapy, and injected interferon
Targeted therapies that identify and attack specific cancer cells
Both skin conditions have their own set of risk factors. Fortunately, Dr. Hwang notes that there is no evidence that having psoriasis or skin cancer increases one's risk of developing the other.
Psoriasis Risk Factors
What sparks the immune system to overreact and cause psoriasis is still a bit of a mystery. Experts believe that a combination of genetics and environmental factors come together to create the perfect storm, resulting in psoriasis, according to NIAMS. However, a few traits seem to increase a person’s risk of developing the condition:
A family history of psoriasis
The presence of specific genes linked to psoriasis
Smoking cigarettes
Obesity
Certain medications
Infections, including strep and HIV
Skin Cancer Risk Factors
No one is immune to skin cancer—anyone can get it. Exposure to UV rays from the sun (or artificial sources, like tanning beds) can contribute to skin cancer development, even if you don’t have any other risk factors, according to the CDC. By using sun protection and avoiding sunburn, you can mitigate your risk of developing melanoma or any other type of skin cancer. Per the CDC, other factors that increase your risk include:
Light skin colour
Skin that burns, freckles, reddens easily, or hurts in the sun
Blue or green eyes
Light natural hair colour (blonde or red)
A large number of moles
A family history of skin cancer
A personal history of skin cancer
Older age
Certain genes or conditions linked to melanoma risk
Getting treatment is essential for both of these skin diseases, as the consequences of leaving them untreated can range from unpleasant to fatal. And because treatment for both psoriasis and skin cancer is most effective in early stages, don’t delay in seeing your doctor for an accurate diagnosis and treatment plan.
Untreated Psoriasis
The biggest issue with leaving psoriasis untreated is that you have to deal with the uncomfortable symptoms, which can disrupt your day-to-day life. “More than 60% of people with psoriasis have very significant itching, so it’s uncomfortable,” Dr. Hwang says. Itchy lesions can also predispose a person to infection, Dr. Rhodes adds. On top of that, the chronic inflammation caused by psoriasis can cause other symptoms, like fatigue, so you may also feel unwell overall. The treatments we have for psoriasis “are very good at removing pain and inflammation,” says Dr. Hwang. “They can help people feel much better.”
Obvious patches of psoriasis on your skin or a flaking scalp can also impact one’s self-esteem. “The visual symptoms are alarming to people and generally considered not cosmetically appealing, so it does have an impact on one's self-image and willingness to go out,” Dr. Hwang notes. “There’s a higher incidence of depression in people with psoriasis, too.”
Untreated Skin Cancer
If you don’t treat skin cancer, it will likely continue to grow. “Skin cancer can be locally destructive and even metastasize if left untreated,” Dr. Rhodes says. Metastasis is a significant concern with melanoma and some rarer forms of skin cancer, but not so much with BCC and SCC, Dr. Hwang notes. “The most common types of skin cancers tend to just grow and get bigger and require more extensive surgeries to remove, some of which can be disfiguring if you don't find it when it's small,” he explains. “If very large areas of skin are involved, surgery can be complex and quite invasive—some people even need skull and bone removed.”
Outlook
Psoriasis and skin cancer are both skin conditions that require a proper diagnosis and treatment to keep you healthy long-term. While psoriasis cannot be cured, it can be managed with the right medications. “We have excellent treatments for psoriasis with new ones approved every year,” Dr. Rhodes notes. “And skin cancer, if caught early enough, is easily treated,” she adds. That’s why it’s imperative to keep tabs on your skin and call your doctor if you notice any new growths or lesions, or think that something old has changed in shape, colour, or size. A clinician can investigate anything that seems suspicious and help you get to the bottom of it.
