How to tell the difference between psoriasis and skin cancer
The most common type is plaque psoriasis, which forms patches of dry, red skin with silvery scales.
Skin cancer is the most common type of cancer in the U.S. The cause is usually sun exposure. Ultraviolet (UV) rays can damage the DNA in skin cells, changing the ways that they grow and divide.
Telling the difference between psoriasis and skin cancer
People may sometimes confuse plaque psoriasis with skin cancer.
Distinct types of psoriasis and skin cancer cause different symptoms. Some can look similar, but there are ways to tell them apart.
There are five types of psoriasis:
- Plaque psoriasis forms patches of dry, red skin with silvery scales.
- Guttate psoriasis causes small red, scaly dots to appear across the body.
- Inverse psoriasis forms red, smooth patches along folds in the skin.
- Pustular psoriasis forms white blisters on the skin, usually on the hands and feet.
- Erythrodermic psoriasis leads to inflammation and redness throughout the body, and it can cause the skin to peel away.
Inverse, pustular, and erythrodermic psoriasis are less common. Also, people are unlikely to confuse these types with skin cancer because the early symptoms are very different.
There are five forms of skin cancer:
People are unlikely to confuse melanoma and Merkel cell carcinoma with psoriasis.
A change in a mole can be an early symptom of melanoma. The American Academy of Dermatology encourages people to monitor their moles for any changes, using the ABCDE method:
- Asymmetry: The two halves of the mole begin to look uneven.
- Border: The edge of the mole becomes irregular.
- Color: One part of the mole has a different tint from the rest.
- Diameter: The mole grows larger than 6 millimeters.
- Evolving: Over time, the mole changes in size, shape, or color.
Merkel cell carcinoma is less common than other forms of skin cancer. The first symptom is usually a red, pink, or purple lump under the skin, which is usually not painful.
The following types of skin cancer and psoriasis can share symptoms, but certain factors, such as the location of a rash, can help a person tell them apart.
|a raised, red patch of skin, which may itch||Plaque psoriasis: The skin may itch as soon as psoriasis develops. It often affects the scalp or the skin covering the joints.||Basal cell carcinoma: These patches are unlikely to itch or bleed until they grow quite large. They are common in areas exposed to the sun, such as the face or shoulders.|
|a scaly, rough patch of skin, which may bleed||Plaque psoriasis: Affected areas are unlikely to bleed unless scratched.||Squamous cell carcinoma: These patches usually form on sun-exposed skin.|
|thick, scaly, raised lesions||Plaque psoriasis: The lesions are red and often form on the scalp or the skin of the joints.||Skin lymphoma: The lesions may appear red or purple, and they can form anywhere on the body.|
|flat or raised spots||Guttate psoriasis: These lesions often look like small dots. The condition usually affects children and young adults.||Kaposi's sarcoma: The purple, red, or brown spots usually form on the legs or face. This type of cancer tends to develop in adults.|
Age can play a key role when distinguishing between the two types of disease. Doctors often diagnose psoriasis in people aged 15–35 years. Skin cancer tends to affect older adults.
Skin cancer usually develops in areas of the body that are exposed to sunlight, such as the face, the back of the neck, and the shoulders.
Psoriasis is more likely to appear on the scalp or the skin of the joints, such as the knees or elbows.
A doctor may refer the person to a dermatologist for an examination.
Anyone with symptoms of either psoriasis or skin cancer should see a doctor. Effective treatments exist for both diseases, and receiving treatment early can reduce the long-term health impacts of each condition.
A doctor will carefully examine the affected areas of skin and run some tests. They are likely to ask about symptoms, such as when the appearance of the skin started to change, and how the changes have evolved.
The doctor may also ask about risk factors, such as a family history of either disease.
They may then make a referral to a dermatologist, a doctor who specializes in skin issues, including psoriasis and skin cancer.
The dermatologist can conduct further examinations and tests, and they may order a skin biopsy. This involves taking a sample of affected skin so that a laboratory can test it for various diseases, including cancer.
Doctors usually prescribe topical creams to treat psoriasis, though people with more severe symptoms may need to take oral medications.
Some people with psoriasis also benefit from phototherapy, which exposes the skin to UV light. A doctor will carefully assess the possible increased risk of skin cancer before recommending this course of treatment for psoriasis.
A person with a family history of psoriasis has a higher risk of developing the condition. Psoriasis affects males and females at equal rates, and it is more common in white people.
While a person cannot prevent psoriasis, they can reduce the severity of symptoms and the number of times symptoms flare up. It can help to avoid triggers, such as stress and tobacco.
A person has a higher risk of developing skin cancer if:
- They have light skin or hair.
- They have a disease that affects their immune system.
- They experience sunburns or tans.
What happens if psoriasis and skin cancer are left untreated?
It is very important to treat skin cancer as soon as it is discovered. If left untreated, cancer can spread.
Psoriasis can also get worse if a person does not receive treatment. Prescription medication can help keep symptoms under control.
When to see a doctor
Check the skin regularly for any changes.
If a person suspects that they have symptoms of skin cancer or psoriasis, they should seek medical advice.
Using sunscreen can help reduce the risk of UV damage.
When a doctor diagnoses skin cancer early, treatment is often relatively easy. It can be simple to remove cancer that affects a small area of skin.
Overall, the outlook for skin cancer depends on the type and stage.
A person can reduce their risk of UV damage by:
- using sunscreen
- avoiding sun exposure during the hottest part of the day
- wearing a hat and long sleeves when outdoors
Psoriasis is a long-term skin condition. With the right treatment, a person can manage symptoms and reduce the impact on daily life. Psoriasis usually does not affect life expectancy.
Psoriasis and skin cancer both change the outer layer of skin. In the diseases' early stages, it can be difficult to tell symptoms apart.
It may be easy to mistake, for example, symptoms of skin cancer for symptoms of plaque or guttate psoriasis.
However, the diseases tend to affect different parts of the body. They also tend to develop in different stages of life.
Doctors can treat or manage psoriasis and skin cancer. Receiving treatment early can lead to a better outcome.