The symptoms of psoriasis impact everyone differently. You might have a couple of irritated patches of skin, while someone else may have a serious outbreak of lesions all over their body. And your mild psoriasis could pretty much stay the same, while someone else’s becomes more severe over time. But why does this happen? Here’s what we know.
What Makes Psoriasis Mild, Moderate, or Severe?
Several factors go into determining whether your psoriasis is considered mild, moderate, or severe. Factors that doctors and researchers consider when determining which category you’re in include:
Coverage. Most people living with psoriasis have a mild form of the condition, covering less than 2% of their skin. That number rises to 3% to 10% with moderate psoriasis. The condition is severe when it covers 10% or more of your body. To figure out a rough estimate, use the palm of your hand as a measuring tool -- it equals about 1%.
Appearance. What do your lesions look like? Are they particularly scaly, thick, or discolored? This means your psoriasis is more severe.
Quality of life. Think about how psoriasis affects your day-to-day life, physically, mentally, and socially. For example, is it hard to bathe properly or wear certain clothing? Are you sometimes embarrassed by the way your skin looks?
Location. Psoriasis on specific areas of your body may mean your condition is more severe. For instance, psoriasis on your scalp, palms, soles, and skin folds (like the inside of your elbow) is harder to treat and a possible sign your condition is serious. A diagnosis of psoriatic arthritis is another clue.
Researchers and doctors also use the Psoriasis Area and Severity Index (PASI) to decide how severe your psoriasis is. They look at how much of your body has psoriasis, how serious your symptoms, and how they impact your quality of life. A PASI score can range from 0 to 100 -- the higher your score, the clearer your skin. However, some researchers think the PASI isn’t accurate enough to determine psoriasis severity.
At least one organization, the National Psoriasis Foundation, wants to update how experts classify psoriasis severity. They suggest two groups based on the treatment type. One for local treatments like those you put directly on your skin or scalp, and the other for drugs you take by mouth in a pill or get as a shot (systemics). Doctors typically prescribe systemics for moderate to severe psoriasis that hasn’t improved with other treatments. Some scientists think treating psoriasis with systemics early on could slow the progression of the disease.
Is Psoriasis Progressive?
A progressive disease or health condition is one that gets worse over time. There’s no scientific proof that psoriasis always becomes more severe. But it can change, even if you’ve had it for a while.
Some people have symptoms once, while others have cycles where they flare up then go away. Or your psoriasis symptoms could stick around. It’s also possible to have a mild form of the skin condition for years that becomes moderate or severe without warning.
Whether your psoriasis is mild, moderate, or severe, inflammation is a constant with the condition and could lead to other health issues. These include:
Psoriatic arthritis (PsA). Around 30% of people with psoriasis will end up with psoriatic arthritis. This type of arthritis, which triggers joint pain, stiffness, and swelling, usually appears 10 years after psoriasis forms. But you may not get psoriasis first (or at all) before PsA starts.
Metabolic syndrome. Metabolic syndrome is a group of health conditions that happen together and raise your chances of heart disease, stroke, and type 2 diabetes. Research links psoriasis to high blood pressure, high blood sugar, extra belly fat, obesity, high levels of “bad” (LDL) cholesterol, and low levels of “good” (HDL) cholesterol.
Cancer. Psoriasis raises your odds of forming cancers of the colon, kidney, larynx (voice box), liver, lymph system, esophagus, mouth, and pancreas. Researchers aren’t sure why, but they think the inflammation psoriasis causes may be a factor.
Cardiovascular disease. Mounting scientific evidence finds a connection between psoriasis and illnesses of the heart and blood vessels like heart disease and stroke.
Mental health conditions. Depression and anxiety are sometimes a part of life with psoriasis. One survey found nearly one-quarter of people with the condition have depression. And, the worse your psoriasis, the more likely you are to become depressed.
Other autoimmune illnesses. When you have psoriasis, your chances of having another autoimmune disease also rise. These conditions include celiac disease, multiple sclerosis, and Crohn's disease.
Why Does Psoriasis Progress to Moderate or Severe?
Right now, researchers don’t fully understand why some mild psoriasis worsens, calling it a “major research gap.” They say learning more about progression can help them predict what may happen and better treat psoriasis and other related illnesses.
Scientists are looking at the role of biomarkers in psoriasis. Biomarkers are signs of a disease, such as a molecule, that can help doctors more accurately predict how a condition may change. They can also help doctors target more specific treatments. While doctors use biomarkers in other conditions of the immune system like rheumatoid arthritis, they haven’t been able to identify any in psoriasis.
We do know that things in your day-to-day life, like changes in the weather or your mood, can lead to a psoriasis flare or make one worse. These include:
Weather. A drop in temperature and moisture are common triggers. Many people find that hot, sunny, and humid weather eases irritated skin. But some forms of psoriasis get worse when exposed to sunlight.
Stress and emotional changes. Your brain and skin are closely connected. Stress can spark an immune reaction in your body, which shows up on your skin as a psoriasis flare. Watch out for mood and mental health changes, too. These include anger, depression, and anxiety.
Infection. Tonsil and sinus infections, strep throat, HIV, and other infections can trigger psoriasis and make it worse.
Skin injuries. An injury to your skin -- even a minor bump or bruise -- can later cause psoriasis to flare up. It’s a reaction called the Koebner response or phenomenon.
Prescription drugs. Talk to your doctor before taking medicine for high blood pressure, heart problems, bipolar disorder, or malaria.
Medication changes. When you stop taking certain medications, particularly steroids, it can worsen psoriasis.