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Medically reviewed by the HealthVetted Medical Board
Psoriasis is a chronic, immune-mediated disease that speeds up the skin's life cycle, so cells pile up into raised, scaly patches called plaques. It is not contagious and there is no cure, but for most people it can be well controlled — and sometimes nearly cleared — with today's treatments.
Psoriasis is a long-term (chronic) inflammatory condition in which an overactive immune system tells skin cells to grow far too quickly. Normally a skin cell takes about a month to rise from the deepest layer of the skin to the surface and shed. In psoriasis this process is dramatically accelerated, so cells reach the surface in days and accumulate before they can fall off. The result is the classic plaque: a thickened, raised patch of skin topped with scale (NIH/NIAMS; StatPearls).
Crucially, psoriasis is not a problem of poor hygiene or an infection — it cannot be caught from or spread to another person. It is an immune-mediated disease, sometimes grouped with other systemic inflammatory conditions, and it is associated with inflammation beyond the skin (AAD/NPF).
There are several recognized types:
In ICD-10 coding, psoriasis falls under L40 (for example, L40.0 for plaque psoriasis and L40.9 for unspecified psoriasis).
Psoriasis results from a combination of genetic susceptibility and immune dysregulation, switched on by environmental triggers (StatPearls; NIH).
The immune mechanism. Psoriasis is driven largely by a pathway involving immune signaling molecules — chiefly tumor necrosis factor-alpha (TNF-α), interleukin-23 (IL-23), and interleukin-17 (IL-17). These cytokines fuel the rapid skin-cell turnover and inflammation seen in plaques, and they are the precise targets of modern biologic medications.
Genetics. Psoriasis runs in families. Many people with psoriasis have a relative with the condition, and numerous susceptibility genes have been identified, the best established being within the HLA-C region (HLA-Cw6). Genes load the dice, but they are not destiny — a trigger is usually needed to set the disease in motion (StatPearls).
Common triggers that can start or flare psoriasis include:
Who's at risk. Risk factors include a family history of psoriasis, smoking, obesity, and significant stress. Psoriasis can begin at any age but commonly first appears between the late teens and the 30s, with a second smaller peak later in life. It affects all skin tones, though it can look different — and is sometimes underrecognized — in people with darker skin.
Psoriasis affects roughly 3% of US adults — an estimated 7 to 8 million people — making it one of the most common immune-mediated diseases (PMID 24388724; National Health and Nutrition Examination Survey [NHANES] data). Reported prevalence is somewhat higher in White adults and lower in Black, Hispanic, and Asian adults in US survey data, though differences in how the disease presents and is recognized across skin tones may play a role.
The hallmark of plaque psoriasis is raised, well-demarcated patches of skin covered with scale. On lighter skin these often look red or pink with silvery-white scale; on darker skin they may appear violet, brown, or grayish with gray scale, which can make the condition harder to recognize.
Common features include:
Typical locations are the elbows, knees, scalp, and lower back, often in a symmetrical pattern, though plaques can appear anywhere. Inverse psoriasis instead favors skin folds.
Beyond the skin: psoriatic arthritis. A significant minority of people with psoriasis — commonly cited as around one in three — develop psoriatic arthritis (PsA), an inflammatory joint disease causing joint pain, stiffness (often worse in the morning), and swelling, sometimes with a sausage-like swelling of fingers or toes (dactylitis). Skin disease usually appears first, but PsA can occur before or without obvious skin involvement. Untreated, it can cause lasting joint damage, so new joint symptoms should always be reported (AAD/NPF).
The course is typically relapsing and remitting: plaques flare and then quiet down, sometimes for long stretches.
There is no single blood test that confirms psoriasis. Diagnosis is usually clinical — a doctor or dermatologist recognizes it from the appearance, the location, and the pattern of the plaques, along with nail changes and personal or family history (StatPearls; AAD).
Skin biopsy. When the diagnosis is uncertain or to distinguish psoriasis from look-alikes such as eczema, fungal infection, or cutaneous lymphoma, a small skin biopsy can be examined under the microscope. Psoriasis shows characteristic features, including thickening of the upper skin layer and collections of immune cells.
Assessing severity. Clinicians grade psoriasis by how much skin is involved and how it affects quality of life:
Screening for related conditions. Because psoriasis is a systemic inflammatory disease, clinicians screen for psoriatic arthritis (asking about joint pain and stiffness) and monitor cardiometabolic health, since psoriasis is associated with a higher likelihood of obesity, type 2 diabetes, high blood pressure, and cardiovascular disease, as well as depression (AAD/NPF; NIH).
Treatment is matched to severity and follows a stepwise approach. The aim is to clear or nearly clear the skin, relieve symptoms, and reduce inflammation — and modern therapy makes clear or near-clear skin a realistic goal for many people (AAD/NPF guidelines).
These measures support every treatment plan:
For mild disease, OTC products can help alongside moisturizers:
When OTC measures and moisturizers are not enough, prescription treatments are added, roughly in this order:
Topical therapies (first-line for mild-to-moderate disease):
Phototherapy (light therapy): For more widespread disease, narrowband UVB is a well-established, effective option delivered in a clinic or sometimes at home. Other forms include excimer laser for localized plaques and, less commonly today, PUVA (psoralen plus UVA).
Systemic and biologic therapy (moderate-to-severe disease):
Current AAD/NPF guidelines support biologics as highly effective options with a favorable benefit-to-risk ratio for moderate-to-severe disease; choice depends on disease pattern, joint involvement, other health conditions, and patient preference (AAD/NPF Joint Guidelines).
When psoriatic arthritis is present, treatment is coordinated with a rheumatologist, and several systemics and biologics (such as TNF and IL-17 inhibitors) treat both skin and joints.
Psoriasis cannot currently be prevented or cured, because the genetic and immune basis is built in. But the disease is highly manageable, and long stretches of clear or nearly clear skin are achievable for many people.
Long-term management rests on a consistent plan: using prescribed treatments as directed, sticking with daily moisturizing, and avoiding personal triggers such as smoking, excess alcohol, untreated infections, and skin injury. Because flares often follow stress or illness, managing those proactively helps.
Equally important is treating psoriasis as a whole-body condition. Guidelines recommend attention to cardiovascular and metabolic health — blood pressure, cholesterol, blood sugar, and weight — and to mental health, since depression and anxiety are more common in people with psoriasis. Regular follow-up allows treatment to be stepped up or adjusted as the disease changes (AAD/NPF; NIH).
See a clinician if you have persistent, scaly patches that don't resolve, if a suspected case of psoriasis is spreading or affecting your scalp, nails, face, or genitals, or if psoriasis is interfering with sleep, work, or quality of life. A dermatologist can confirm the diagnosis and tailor treatment.
Seek prompt or urgent medical care for these red flags:
Erythrodermic and generalized pustular flares need same-day or emergency evaluation.
For most people, the long-term outlook is good. Psoriasis is a lifelong, relapsing-remitting condition rather than a steadily worsening one, and the great majority of people have mild-to-moderate disease that responds well to treatment. Today's options — from improved topicals to phototherapy, oral small molecules, and targeted biologics — mean that clear or nearly clear skin is a realistic goal that was not achievable a generation ago (AAD/NPF; NIH).
The main challenges are the chronic, fluctuating course, the visible nature of the disease and its effect on confidence and mental health, the risk of psoriatic arthritis, and the associated cardiometabolic and cardiovascular risks. Addressing these proactively — with consistent skin treatment, joint screening, attention to heart and metabolic health, and mental-health support — is central to living well with psoriasis. With appropriate care, most people lead full, active lives.
Is psoriasis contagious? No. Psoriasis cannot be caught from or passed to another person through touch, sharing items, or any other contact. It is an immune-mediated disease driven by genetics and the immune system, not by an infection.
What's the difference between psoriasis and eczema? Both cause discolored, scaly patches, but they differ. Psoriasis typically forms thicker, sharply defined plaques with silvery scale on areas like the elbows, knees, scalp, and lower back, and is often only mildly itchy. Eczema is usually intensely itchy, tends to appear in skin creases, and is closely linked to allergies and asthma. A dermatologist can tell them apart, occasionally with a biopsy.
Will my diet cure my psoriasis? No diet cures psoriasis. However, because psoriasis is linked with obesity and cardiometabolic disease, losing excess weight can improve the skin and treatment response, and limiting alcohol may help. A balanced, anti-inflammatory pattern of eating supports overall health, but it is an addition to — not a replacement for — medical treatment.
Does having psoriasis mean I'll get arthritis? Not necessarily, but the risk is meaningful. A notable share of people with psoriasis — commonly cited as roughly one in three — develop psoriatic arthritis. The skin disease usually comes first, sometimes years before joint symptoms, so it's important to report any new joint pain, stiffness, or swelling so it can be treated early.
Can psoriasis go away on its own? Psoriasis can go into remission, sometimes for months or years, and individual plaques can clear. But because the underlying immune and genetic drivers remain, it is considered a lifelong condition that tends to return. Ongoing management keeps it controlled rather than waiting for it to disappear permanently.
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*This page is for general education and is not medical advice. Psoriasis varies from person to person; talk with a qualified healthcare professional about diagnosis and treatment that's right for you.*
No. Psoriasis is not contagious — you cannot catch it from or pass it to another person through touch, sharing items, or any other contact. It is an immune-mediated condition driven by a combination of genetics and triggers, not by bacteria or viruses that spread between people. Although plaques can look concerning, they pose no risk to others. Education about this can help reduce the social stigma many people with psoriasis experience.
Common triggers include infections (especially strep throat), emotional or physical stress, skin injuries such as cuts and sunburn, smoking, heavy alcohol use, obesity, and cold, dry weather. Certain medications — including lithium, beta-blockers, antimalarials, and abruptly stopping oral steroids — can also provoke flares. Triggers vary from person to person, so keeping a symptom diary can help you and your clinician identify and avoid your personal triggers.
There is currently no cure for psoriasis, but it can be managed effectively. Treatments aim to slow the rapid skin cell growth, reduce inflammation, and clear or shrink plaques. Many people achieve long periods of clear or nearly clear skin with topical treatments, phototherapy, or systemic and biologic medications. Psoriasis typically follows a pattern of flares and remissions over a lifetime, so ongoing management with a clinician is usually needed.
Both cause itchy, inflamed skin, but they differ. Psoriasis produces well-defined, thick plaques with silvery scale, often on the elbows, knees, and scalp, and is driven by overactive immune signaling. Eczema (atopic dermatitis) tends to cause less defined, intensely itchy, sometimes weepy patches, often in skin folds, and is linked to a weakened skin barrier and allergies. Because they can look alike, a clinician sometimes uses a skin biopsy to tell them apart.
Yes. Up to about 30% of people with psoriasis develop psoriatic arthritis, which causes joint pain, stiffness, and swelling. Psoriasis is also associated with a higher risk of cardiovascular disease, metabolic syndrome, type 2 diabetes, and mental health conditions such as depression and anxiety. Because of these links, clinicians often monitor overall health, not just the skin, and may recommend lifestyle changes to lower related risks.
See a clinician if you have persistent skin patches that don't improve with over-the-counter care, are painful or widespread, or affect your scalp, nails, or daily life. Get prompt medical attention for new joint pain or swelling, which may signal psoriatic arthritis, and seek urgent care for a sudden, widespread, peeling or blistering rash with fever, which can be a serious emergency requiring immediate treatment.
This page is for general information and is not medical advice. Always consult a qualified clinician about diagnosis and treatment. Individual results vary.