If you’re experiencing thick, raised, scaled spots on your skin that won’t go away, you may have plaque psoriasis. Psoriasis is a common, chronic disease that, across its various forms, often causes uncomfortable, spreading skin lesions. Psoriasis usually emerges in early adulthood and affects about 3 percent of Americans.
People of all ages and skin colors can develop the disease. The exact causes of psoriasis remain unknown. We do know that psoriasis symptoms arise when an overactive immune system makes skin cells grow faster than usual. This causes the skin in affected areas to become inflamed, which then causes the skin to itch, hurt, flake, and sometimes crack and bleed.
Often, this inflammation and skin cell buildup leads to the formation of distinctive lesions called plaques. Plaque psoriasis is the most common form of psoriasis, affecting from 80 to 90 percent of all psoriasis patients.
In this article, I’ll further explain what plaque psoriasis is, including how doctors classify the disease according to levels of severity. I’ll discuss what we know about the causes and triggers of plaque psoriasis outbreaks and offer an overview of where it’s most often located on the body. I’ll explore how plaque psoriasis is diagnosed and treated, and what it means for it to be in remission.
Finally, I’ll tell you when you should see your doctor about plaque psoriasis.
What is Plaque Psoriasis?
Plaque psoriasis occurs when a person’s disrupted immune system causes skin cells to grow about five times faster than they usually would. Like all forms of psoriasis, plaque psoriasis is not a contagious disease—you can’t give it to someone else. Under normal circumstances, skin cells grow, mature, and exfoliate (fall off) in a cycle that takes about a month.
In areas affected by psoriasis, that process can take as little as four days, and the extra skin cells that are created don’t always slough off. Instead, inflamed skin cells build up to form scales or patches that can itch, crack, hurt, and bleed.
Among psoriasis patients, the most common shape this buildup takes is the raised plaque. These are red or purple patches of thick, raised skin that is often covered with sheddable, whitish scales.
In their earliest forms, psoriatic plaques appear as pinhead-sized red or purple bumps. These bumps then begin to spread, connect and rise in profile until they develop their typically thick, patch-like form.
In more severe cases of psoriasis, these patches themselves can spread and connect to cover more and more of the body’s surface area.
Classification & severity
Plaque psoriasis is not life-threatening, but it is a chronic illness for which there is no permanent cure.
And for those who develop more intense plaque psoriasis symptoms, the disease can significantly affect quality of life for the worse.
The approach your doctor takes to treating psoriasis will depend on how severely it presents itself.
The three classification tiers for plaque psoriasis are:
- Mild: Psoriasis covers less than 3% of your body. Symptoms can usually be controlled by routine skincare (moisturizing, cleansing) or topical treatment.
- Moderate: Psoriasis covers 3-10% of your body. Symptoms cannot be controlled by routine skincare, and/or significantly affect quality of life.
- Severe: Psoriasis covers more than 10% of your body. Symptoms cannot be controlled by topical treatment, and/or severely degrade quality of life.
Scientists haven’t been able to pinpoint the exact causes of plaque psoriasis. Genetics seem to play a role, but not everyone with a genetic predisposition towards psoriasis will develop it.
What we do know is that both the immune system and genetics contribute to psoriasis development. We also know that for people who develop plaque psoriasis, certain triggers often cause it to appear for the first time, or cause it to come back or spread after a period of remission.
Common triggers include:
- Injury to the skin such as cuts, scrapes, severe sunburn, or surgery
- Infections such as strep throat, tonsillitis, bronchitis, and skin infections
- Starting or stopping medication
- Excessive smoking or alcohol consumption
- Severe vitamin D deficiency
- Hormonal changes like those during puberty, pregnancy, postpartum, and menopause
- Cold, dry weather
- Food allergies
Locations on the Body
Plaque psoriasis can appear on most regions of the body. Plaques themselves can take form as a few small patches or can spread to cover large areas.
Some people develop psoriasis plaques in multiple places at once. Most often, plaque psoriasis will develop symmetrically: if plaques appear on the right knee, for instance, they are probably also present on the left knee, as well.
The places most commonly affected by plaque psoriasis are:
- Lower back
Plaques can also appear on other parts of the limbs, and in rarer cases can also appear on the hands, knees, and face.
Primary care health providers are trained to tell psoriasis apart from other rashes like eczema or a fungal infection. To do so, doctors rely on psoriasis’s distinctive spreading patterns and visual features (such as whitish scales, a “raised” profile).
While your doctor examines your rash, they will also interview you about your health, and whether any family members have had psoriasis in the past. In rare cases, they may take a small biopsy (a skin sample) to help determine what kind of psoriasis you have.
A portion of psoriasis patients also develop a related arthritis condition called psoriatic arthritis (PsA). Tell the doctor if you experience any joint stiffness, swelling, or pain. This is a more severe condition and can require more intensive treatments.
There is no permanent cure for psoriasis. Even if symptoms recede following a course of treatment, they could always come back. Just because it can’t be cured doesn’t mean psoriasis symptoms can’t be treated.
There are a number of safe and effective treatment options that have been shown to significantly reduce the size and severity of psoriasis plaque lesions. The goal of most treatments is to shrink your plaques to 1% or less of your skin surface area within three months.
The most common treatments for psoriasis are topical creams, ointments and steroids. These include over-the-counter and prescription corticosteroids, which reduce inflammation by slowing the body’s immune response.
Other active ingredients in topical treatments might include synthetic vitamin D3, salicylic acid, and vitamin A (retinoids). For moderate and severe psoriasis, you might be referred to a dermatologist.
These specialists may turn to a wider range of prescription-strength treatment options.
Doctors often prescribe oral medication to people with moderate to severe psoriasis that doesn’t respond well to topicals. Taken orally, certain types of retinoids, steroids, immunosuppressants, and anti-rheumatic drugs can reduce inflammation (and therefore reduce plaques) by working on the immune system as a whole.
These prescription medications are known as oral systemics.
Sometimes, corticosteroids and other systemic medications are injected directly into psoriasis plaques or lesions. Doctors might also opt for a class of injectable psoriasis medications called biologics.
Compared to systemic medications, biologics work by targeting more specific cells and parts of the immune system—in this case, those that are tied to psoriasis and PsA. Drugs in this category include etanercept (Enbrel), adalimumab (Humira), and infliximab (Remicade).
These biologics can also be taken by IV infusions.
When used in controlled settings like the doctor’s office, or with a special home-care kit, ultraviolet light B (UVB light) can soothe inflamed skin and relieve symptoms.
UV light administered in this way can interrupt the patterns of skin cell growth that lead to plaques.
Your doctor might suggest that you supplement your medication with complementary lifestyle changes such as improving your diet, becoming more physically active, learning how to reduce your stress, and getting acupuncture.
- A diet low in inflammatory foods may help, however, this is not fully vetted.
- Daily warm baths with oatmeal, epsom salt, or certain oils can help remove the buildup of skin cells.
- Be careful not to scrub too hard or use harsh chemical soaps.
- Natural salves like aloe vera may also provide soothing symptom relief.
- Consult with your healthcare provider before starting any natural home remedies.
While these natural treatments and lifestyle changes may help alleviate your symptoms, they are not appropriate replacements for pharmaceutical medication.
Every psoriasis patient is different, and it can be hard to predict which treatments your plaque psoriasis will respond most to. It’s also hard to know how long your psoriasis will stay in remission if it does go away or shrink to less than 1% of the skin area.
Individuals who have psoriasis experience symptoms that cycle through periods of remission and exacerbation. It’s hard for doctors to know which plaque psoriasis patients will relapse, and how often.
With time, however, you’ll be able to observe which triggers seem to be most linked with a resurgence of plaque growth. Even when your psoriasis is in remission, check in with your doctor every six months to review how well your disease management approaches are working.
When people become stressed or come into contact with a triggering substance, their immune system goes into overdrive, causing psoriasis symptoms to flare.
Managing stress as a psoriasis trigger can be challenging when the disease itself is a major source of stress and worry (even in periods of remission). Some of the biggest ways that psoriasis affects quality of life fall in the realm of mental health: Severe outbreaks—or even the fear of outbreaks—can cause depression, isolation, and stress.
Therapy, as well as virtual and in-person psoriasis support groups, can help you manage the mental side of the disease.
When to See a Doctor
If you are concerned about an itchy, red, or raised patch of skin, see your primary doctor or dermatologist to get it accurately diagnosed. See a healthcare provider if you have a rash of any kind that lasts longer than a week.
Raised skin that is painful, flaky, peeling, or bleeding is of special concern. If you are experiencing a severe, sudden psoriasis outbreak covering most of your body, seek emergency care immediately.
Full-body psoriasis outbreaks disrupt your body’s ability to regulate temperature and fluids and can be life-threatening.
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Frequently Asked Questions
K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.
K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.
Psoriasis Prevalence in Adults in the United States. (2021).
Comparative Analysis of Small and Large Plaque Psoriasis. (2016).
Plaque Psoriasis. (2021).
“Diagnosis and management of psoriasis.” (2017).
“About Psoriasis.” (2021).
Plaque psoriasis. (2022).