Your skin is itchy, red and dry. You can’t stop scratching. Google tells you it’s eczema.
But wait. Before you rush out to a pharmacy, there’s another skin condition that can have visually similar symptoms and your eczema cream probably won’t work for it: psoriasis.
Eczema and psoriasis are like twins — they have a similar look, but deep down, they are fundamentally different.
Eczema and Psoriasis: How Similar Can They Be?
Both eczema and psoriasis can cause a rash — patches of red, raised, itchy skin — and they can appear in the same places of the body, such as the hands and scalp. Neither is contagious but both can lead to infections. An experienced dermatologist may be able to spot the differences, but to the untrained eye, it’s hard to tell.
Although eczema can be more prevalent in the United States, psoriasis is also common. This makes self-diagnosis even harder, because the chance for getting either condition is high.
However, despite the confusingly similar appearances, there are clues that can help you tell them apart.
1. Genetics, Environment or Autoimmune: Which Causes Which
"The biggest difference between eczema and psoriasis is the underlying causes. Psoriasis is an autoimmune disease, meaning your immune system is dysfunctional and your skin cells grow too fast. The cells start to pile up on the top of the skin, forming the white scale," explains Jeffrey Millstein, MD, a physician at Penn Internal Medicine Woodbury Heights.
The cause of eczema is much more complicated and hard to determine. Both genetic and environmental factors could play a role in triggering the rash.
Researchers have found in some eczema patients that a gene responsible for creating a protective layer on the top of the skin has mutated (changed), which leaves the skin prone to infection and flare. Climate can also play a role — people living in a dry climate or city where they are exposed to pollutants often have dry skin.
2. Subtle Differences in Itchiness
True — when you’ve got an irritating, itchy spot, who cares about the subtle difference? But this can help you and the dermatologist to decide which skin condition you are having.
Dr. Millstein says, "Psoriasis tends to cause milder itching and, in some less common types of psoriasis, a terrible burn. Eczema, on the other hand, can lead to very intense itching. When it starts to become severe, some people scratch their skin so hard that it bleeds."
Both skin diseases can show up anywhere on your body, but they have their own favorite areas.
Psoriasis causes troubles commonly on the:
- Scalp
- Elbows
- Knees
- Buttocks
- Face
Eczema can occur in those places, but it most often inflames the skin on the back of the knees or the inside of the elbows.
Although you can get either disease at any age, eczema affects children more than psoriasis does.
3. Sunshine Can Ease Psoriasis But Not Necessarily Eczema
If you have eczema, summer might not be your favorite season. Some people with eczema are sensitive to heat. In hot weather, overheating can cause perspiration, which can lead to skin flare.
"However, for most psoriasis patients, abundant natural ultraviolet B (UVB) light from sunshine can be a blessing. UVB light can slow down the abnormal growth of skin cells. It is used as a medical treatment for psoriasis," says Dr. Millstein.
But remember — too much of a good thing can become damaging. If you go sunbathing without using sunscreen or are exposed to sunlight for too long, overexposure can trigger psoriasis symptoms. If you start to feel itchy or see red spots, get out of the sun. Make sure to talk to your dermatologist about the best amount of time for exposure to the sun.
Getting Treated
If you have itchy, red patches on any part of your body that don’t go away with over-the-counter medications, it’s better to see a dermatologist directly. Primary care providers can also help make a diagnosis and manage your symptoms, but a dermatologist has specialized training and extensive experience in recognizing subtleties of the two skin conditions.
The treatments for eczema and psoriasis are similar. Some of the common treatments include:
- Over-the-counter relief: Many of these products are aimed to help relieve symptoms or prevent infection.
- Topicals: These are medications your doctor prescribes for you to apply on the affected skin.
- Phototherapy: Also known as light therapy, phototherapy uses a machine to create UVB light. Phototherapy is safe — you will only be exposed to a healthy, controlled amount of UVB light, and the procedure is performed under medical supervision. This can reduce itching and inflammation, and boost bacteria-fighting ability of the skin.
- Biologics: These are medications that can target the protein that makes you have the inflammation response. They’re usually given by injection or intravenous (IV) infusion.
- Systemics: These are medications you can take by mouth to control your immune system response and reduce inflammation. It’s often prescribed to you if your condition is severe.
Eczema and psoriasis can present very differently in each person. Comparing your symptoms to another patient’s won’t always give you the right answer. Talk to a dermatologist about getting the right diagnosis and treatment.