Psoriasis is a chronic inflammatory skin disease that affects millions of people worldwide. Psoriasis affects approximately 3.0% of adults in the United States (1), while the prevalence worldwide ranges from 0.51% to 11.43% (2). The condition is more common in countries farther from the equator (3).
Table of Contents
What Is Psoriasis?
Psoriasis is a disease where your immune system mistakenly attacks healthy skin cells. This causes skin cells to multiply much faster than normal. The rapid buildup creates thick, scaly patches on your skin.
Research shows that T cells (a type of white blood cell) play a central role in causing psoriasis (4).
Is Psoriasis Contagious?
Psoriasis is not contagious. You cannot catch it from someone else or spread it to others through physical contact. The condition results from your own immune system attacking your skin cells, not from any infection that can be passed between people.
Common Symptoms of Psoriasis
The most common signs of psoriasis include thick, red patches of skin covered with silvery-white scales. However, symptoms can vary depending on the type of psoriasis you have.
When examined closely, psoriatic skin shows regularly distributed red dots. At higher magnification, these appear as tiny blood vessels called capillary bushes. The background color is usually reddish or pinkish with white or yellowish scales (5).
Types of Psoriasis
There are several types of psoriasis, each with distinct features:
Plaque Psoriasis: The most common type, causing raised, red patches covered with silvery scales.
Guttate Psoriasis: Appears as small, drop-shaped spots. It’s often triggered by strep throat infections (6).
Pustular Psoriasis: Forms white pustules (blisters of noninfectious pus) surrounded by red skin. Low-dose cyclosporine treatment helps about 89% of patients with palmoplantar pustulosis (7).
Erythrodermic Psoriasis: A severe form that can cover your entire body with a red, peeling rash. More than 50% of patients see significant improvement with cyclosporine treatment (8).
Inverse Psoriasis: Appears in skin folds like armpits, groin, and under breasts. About 71% of patients achieve clear or almost clear skin with pimecrolimus cream after 8 weeks (9).
Common Areas Affected
Psoriasis can appear anywhere on your body, but certain areas are more commonly affected:
- Scalp: Shows red dots and twisted red loops
- Elbows and knees: Often the first areas to develop symptoms
- Palms and soles: Can be especially hard to treat
- Nails: Causes nail separation, salmon-colored patches, and tiny hemorrhages
- Genital area: Affects quality of life and sexual function
About one-third of patients with palm and sole psoriasis achieve clear or almost clear skin with newer treatments (10).
Psoriasis Cycles and Remission
Psoriasis often follows a pattern of cycles. You may experience severe symptoms for days or weeks, followed by periods when symptoms improve or disappear completely. These quiet periods are called remission.
During remission, you may have no visible signs of psoriasis. However, this doesn’t mean the condition is cured. Psoriasis can return when triggered by stress, infections, or other factors. Some people enjoy long periods of remission, while others have more frequent flare-ups.
Who Gets Psoriasis?
Psoriasis can affect anyone, but certain patterns exist in who develops the condition and when.
Age Patterns
Psoriasis typically appears at two peak ages. The first peak occurs around 30-39 years old, and the second happens at 60-69 years. Women tend to develop psoriasis slightly earlier than men (11).
Geographic Differences
Where you live affects your risk of psoriasis. In Italy, between 1.8% and 4.8% of people have psoriasis (12).
What Causes Psoriasis?
Psoriasis happens when your genes, immune system, and environment interact in specific ways.
Genetic Factors
Scientists have identified 63 genetic locations linked to psoriasis. These genes explain about 28% of why psoriasis runs in families (13).
Recent research has found even more psoriasis genes. Scientists now know of 109 distinct genetic locations linked to psoriasis, including 46 newly discovered ones (14).
One specific gene variant called HLA-Cw*0602 strongly increases psoriasis risk. People with this gene variant are 4.55 times more likely to develop psoriasis (15).
Immune System Problems
Your immune system plays a key role in psoriasis. A protein called IL-17A is particularly important in psoriatic skin. This makes IL-17A a specific target for psoriasis treatments (16).
Certain protein complexes called inflammasomes also contribute to psoriasis. These include NLRP1, NLRP3, and AIM2, which activate inflammation in the skin (17).
Risk Factors and Triggers
Several factors can increase your risk of developing psoriasis or trigger flare-ups.
Stress
Psychological stress is linked to psoriasis onset, flare-ups, and severity. Higher stress levels correlate with worse psoriasis symptoms (18).
Smoking
Smoking significantly increases psoriasis risk. Current smokers are 1.88 times more likely to develop psoriasis. The more you smoke, the worse your psoriasis may be (19).
Genetic studies confirm smoking causes psoriasis. Starting to smoke increases your risk by 46%. Each additional cigarette per day increases risk by 38% (20).
Obesity
Higher body weight increases psoriasis risk. For every 5-point increase in BMI, psoriasis risk goes up by 19%. The lowest risk is at a BMI around 20 (21).
Each 1-point increase in BMI increases psoriasis odds by 9% (22).
Infections
Certain infections can trigger psoriasis, especially a type called guttate psoriasis. Strep throat is closely linked to guttate psoriasis in children and young adults. However, antibiotics don’t help established psoriasis (6).
Stomach bacteria called H. pylori are also linked to psoriasis. Psoriasis patients are 19% more likely to have H. pylori infection. Those with moderate to severe psoriasis show an even stronger link (23).
Health Conditions Associated with Psoriasis
Psoriasis affects more than just your skin. It’s linked to many other health conditions.
Psoriatic Arthritis
About one in five people with psoriasis develop psoriatic arthritis. A large analysis found that 19.7% of psoriasis patients have this joint condition. In children, only 3.3% develop it. Risk factors include nail problems, scalp psoriasis, and widespread skin disease (24).
Metabolic Syndrome
People with psoriasis are 2.26 times more likely to have metabolic syndrome. This includes high blood pressure, high blood sugar, excess belly fat, and abnormal cholesterol. The risk increases with more severe psoriasis (25).
Globally, 32% of psoriasis patients have metabolic syndrome. In Latin America, rates reach 47% (26).
Heart Disease
Psoriasis increases your risk of heart problems. Mild psoriasis has shown to raise heart attack risk by 29% and stroke risk by 12%. Severe psoriasis increases heart attack risk by 70% and stroke risk by 56% (27).
Type 2 Diabetes
Psoriasis patients have 59% higher odds of diabetes. Mild psoriasis increases diabetes risk by 53%. Severe psoriasis nearly doubles the risk (28).
Psoriasis and diabetes share genetic pathways involving inflammation. This helps explain why these conditions often occur together (29).
Mental Health Conditions
Living with psoriasis affects mental health. Depression affects more than 10% of psoriasis patients. About 28% experience depressive symptoms. Psoriasis patients are 57% more likely to have depression (30).
Anxiety affects psoriasis patients at these rates:
- Social anxiety disorder: 15%
- Generalized anxiety disorder: 11%
- Overall anxiety symptoms: 34%
Psoriasis patients have 48% higher odds of anxiety disorders (31).
Most concerning, psoriasis patients are twice as likely to have suicidal thoughts. They have 26% higher odds of suicide attempts. Younger patients with severe psoriasis face the highest risk (32).
Other Associated Conditions
Inflammatory Bowel Disease: People with psoriasis have 70% higher odds of Crohn’s disease and 75% higher odds of ulcerative colitis (33).
Sleep Disorders: Between 36-82% of psoriasis patients have sleep apnea, compared to just 2-4% in the general population. About 15-18% have restless legs syndrome compared to 5-10% normally (34).
Kidney Disease: Psoriasis patients have 34% higher risk of chronic kidney disease and 29% higher risk of end-stage kidney disease (35).
Impact on Quality of Life
Psoriasis affects every aspect of daily life, from physical comfort to emotional wellbeing.
Studies show psoriasis impacts (36):
- Physical comfort
- Emotional functioning
- Body image
- Daily activities
- Social interactions
- Work performance
Pain and discomfort cause the biggest impact on quality of life. More severe psoriasis leads to worse quality of life scores (37).
Diagnosis and Assessment
Doctors diagnose psoriasis by examining your skin. They use special tools to measure severity and track progress.
How Psoriasis Is Diagnosed
Most doctors can diagnose psoriasis with a simple physical examination. The symptoms are usually clear and easy to distinguish from other skin conditions. During the exam, your doctor will look at all affected areas and ask about family history of psoriasis.
Sometimes, if the diagnosis isn’t clear, your doctor may take a small skin sample (biopsy). This helps confirm psoriasis and rule out other conditions. Currently, there are no clinical examination-based diagnostic criteria for psoriasis, though various diagnostic models have been developed (38).
Measuring Psoriasis Severity
Healthcare providers use several tools to assess psoriasis:
PASI Score: The Psoriasis Area and Severity Index scores from 0 to 72. It’s the most widely studied severity measure (39).
BSA: Body Surface Area measures what percentage of your body has psoriasis.
PGA: Physician’s Global Assessment uses a simple 5-point scale.
Many patients with scores below 10 on PASI or BSA still have major quality of life problems. Current scoring thresholds may not capture the full patient impact (40).
Treatment Overview
Psoriasis treatment options range from creams to advanced medications. Your doctor will choose based on severity, location, and your specific needs.
Topical Treatments
For mild to moderate psoriasis, topical treatments come first. Strong corticosteroids work best, especially when combined with vitamin D creams. These combinations help many patients achieve clear or nearly clear skin (41).
Phototherapy
UV light therapy helps many patients. Narrowband UV-B phototherapy clears psoriasis in 60-90% of patients within 20-40 sessions. It has fewer side effects than older light treatments (42).
Systemic Treatments
For moderate to severe psoriasis, pills or injections work throughout your body:
Traditional Medications: Methotrexate helps about 45% of patients achieve 75% improvement at 16 weeks (43).
Biologics: These newer targeted therapies have transformed psoriasis treatment. Many patients achieve 90% improvement or complete clearance (44).
Living with Psoriasis
Managing psoriasis requires a complete approach that addresses physical symptoms, emotional health, and lifestyle factors.
Lifestyle Changes
Several lifestyle modifications can help manage psoriasis:
Weight Management: Maintaining a healthy weight through proper diet and exercise can improve symptoms and help treatments work better.
Stress Reduction: Since stress triggers flares, techniques like meditation, yoga, or counseling can help.
Avoiding Triggers: Identify and avoid your personal triggers. Common ones include certain foods, alcohol, smoking, or skin injuries.
Skin Care: Regular moisturizing and gentle cleansing help manage symptoms. Many people find home remedies helpful as additional treatments.
Nutritional Approaches
While diet alone won’t cure psoriasis, certain foods and nutrients may help. Some people benefit from anti-inflammatory diets. Others find relief with specific vitamins and supplements. Natural herbs have also shown promise in some studies.
Future Outlook
Research continues to advance our understanding of psoriasis. New genetic discoveries reveal more treatment targets. Better understanding of the immune system leads to more precise therapies.
Scientists are studying the gut microbiome, environmental factors, and personalized medicine. These approaches promise to transform psoriasis care in coming years.
Conclusion
Psoriasis is a complex disease that affects far more than your skin. While it presents challenges, understanding the condition helps you work effectively with healthcare providers.
Remember that psoriasis affects each person differently. What works for one person may not work for another. Personalized treatment plans are essential.
With proper management combining medical treatment, lifestyle changes, and emotional support, most people with psoriasis can achieve good disease control and maintain quality of life.
If you think you have psoriasis or are struggling with your current treatment, see a dermatologist. They can develop a treatment plan tailored to your specific needs.