Psoriasis – Causes, Symptoms, Treatments

What is Psoriasis?

Psoriasis is an autoimmune disease that causes skin cells to reproduce at an abnormally fast rate. This rapid turnover of skin cells leads to a buildup of dead skin cells on the surface of the skin, which forms the characteristic plaques of psoriasis. These plaques can be red, inflamed, and itchy, and they can sometimes crack and bleed.

Impact on the Skin

• Plaques: The most common symptom of psoriasis is the development of thick, red, scaly patches on the skin, called plaques. These plaques can appear anywhere on the body, but they are most commonly found on the elbows, knees, scalp, and lower back.
  
  
• Itching and burning: Psoriasis can cause intense itching and burning, which can be very uncomfortable and make it difficult to sleep.
  
  
• Cracking and bleeding: Psoriasis plaques can crack and bleed, especially if they are scratched.

Psoriasis is caused by an overactive immune system. In normal skin, skin cells grow and then die and shed over the course of about a month. In psoriasis, this process is sped up to just a few days. This rapid turnover of skin cells leads to the buildup of dead skin cells that form the plaques of psoriasis.

Psoriasis is surprisingly widespread. Estimates range from 100 million to 125 million people globally affected, representing 2-3% of the total population. Data availability varies, with only 19% of countries having official epidemiological data on psoriasis prevalence [Global Psoriasis Atlas].

The prevalence of Psoriasis in children is generally below 1% across all countries [Global Psoriasis Atlas]. In adults, however, that prevalence varies by region with 0.17% in East Asia to 2.50% in Western Europe [Global Psoriasis Atlas].

This suggests psoriasis can strike at any age, but adulthood seems to be more common based on prevalence data. It’s important to note that underdiagnosis might be a factor, especially in children or people with darker skin tones.

Risk Factors of Psoriasis 

Psoriasis, a chronic autoimmune disease characterized by rapid skin cell turnover, has a complex origin story. Researchers believe it arises from a combination of genetic predisposition and environmental triggers that nudge the immune system into overdrive.

Genetics play a significant role. If a close relative has psoriasis, your chances of developing it increase to 10-30% compared to the general population [American Academy of Dermatology]. Scientists have identified specific genes associated with psoriasis, but these genes don’t directly cause the condition. Instead, they seem to influence how the immune system responds to external factors.

These external factors, if present in someone with a genetic predisposition, can trigger an autoimmune response. Common triggers include skin injuries like cuts or sunburns, infections such as strep throat, and even emotional stress. Certain medications, cold and dry weather, smoking, and obesity have also been linked to psoriasis onset or worsening of symptoms.

The exact way these triggers work is still being unraveled, but a few leading theories provide some insight. One theory centers on T-cells, a type of white blood cell responsible for fighting infections. In psoriasis, T-cells become overactive and mistakenly target healthy skin cells as if they were a threat. This triggers inflammation and accelerates skin cell growth.

Another theory focuses on cytokine production. Overactive T-cells release inflammatory molecules called cytokines, which act like a cellular communication system. In psoriasis, these cytokines further accelerate skin cell growth, leading to the characteristic plaques and scaling.

The final theory suggests a broader immune system dysregulation. The intricate interplay between genes and environmental factors might disrupt the normal checks and balances within the immune system. This disruption can lead to an inappropriate attack on healthy skin cells, causing the rapid turnover that defines psoriasis.

Types of Psoriasis

Psoriasis expresses itself in a variety of forms, each with distinct characteristics. While the underlying cause is rooted in an autoimmune response, the way it manifests on the skin can differ. Here’s a closer look at the most common types of psoriasis and their unique presentations:

Plaque Psoriasis: The Widespread and Classic Form

Plaque psoriasis holds the title of the most common type, affecting roughly 80% of people with psoriasis. It manifests as raised, red, scaly patches on the skin, aptly named plaques. These plaques tend to favor certain areas like the elbows, knees, scalp, and lower back. However, they are not limited to these locations and can appear anywhere on the body. Itching, burning, and sometimes even cracking and bleeding are some of the unpleasant symptoms associated with plaque psoriasis.

Guttate Psoriasis: Droplets Triggered by Infection

Guttate psoriasis often follows a bacterial infection, particularly strep throat. It develops as small, red, teardrop-shaped lesions on the torso, limbs, and scalp. Unlike the thicker, more substantial plaques of plaque psoriasis, these lesions are typically smaller and have less scaling. This type of psoriasis is more commonly diagnosed in children and young adults.

Inverse Psoriasis: Targeting Smooth and Folded Skin

Inverse psoriasis strikes a different path, targeting the smooth, hairless areas of the body. This includes the armpits, groin, and genitals. In contrast to plaque psoriasis, the patches here appear smooth, red, and inflamed, lacking the characteristic silvery scales. Friction and moisture in these fold areas can worsen the discomfort caused by inverse psoriasis.

Pustular Psoriasis: A Less Common But More Severe Form

Pustular psoriasis is a less frequent but more severe form of the condition. It’s characterized by white pustules, which are sterile blisters, erupting on red and inflamed skin. There are two main subtypes to be aware of:

• Generalized pustular psoriasis: This rare and serious form involves widespread pustules erupting across the body, often accompanied by fever, chills, and fatigue. Immediate medical attention is crucial in such cases.
• Palmoplantar pustulosis: This subtype exclusively affects the palms of the hands and soles of the feet. The pustules in this case are small and sterile.

Erythrodermic Psoriasis: The Rarest and Most Serious Form

Erythrodermic psoriasis is the rarest and most concerning form, affecting up to 2% of people with psoriasis. It manifests as widespread redness, scaling, and inflammation that can cover most of the body’s surface. This severe form can be life-threatening and requires immediate medical intervention.

Nail Psoriasis: Impacting the Nails

Nail psoriasis can occur independently or alongside other types of psoriasis, affecting up to half of people with the condition. Symptoms to watch for include pitting in the nail surface, discoloration, thickening of the nail plate, and separation of the nail from the underlying nail bed. Psoriatic nails can be painful and make everyday activities difficult.

Scalp Psoriasis: An Itchy and Uncomfortable Variant

Scalp psoriasis is a common variant that often co-exists with plaque psoriasis elsewhere on the body. It presents as thick, red, scaly patches on the scalp, causing itching and discomfort. In some cases, scalp psoriasis can extend beyond the scalp, affecting the forehead, ears, and back of the neck.

Psoriasis Outbreak Triggers

Psoriasis, while not fully understood, has several well-documented triggers that can worsen symptoms or induce flare-ups. These triggers can be broadly classified into internal and external factors, and they can influence the underlying autoimmune response in different ways.

Internal Triggers:

• Stress: Emotional stress is a well-known trigger for psoriasis flare-ups. When stressed, the body releases hormones like cortisol that can exacerbate inflammation and accelerate skin cell turnover. This can lead to the formation of new psoriatic plaques or worsen existing ones.
  
  
• Medications: Certain medications can trigger or worsen psoriasis. Some common culprits include beta-blockers for high blood pressure, lithium for bipolar disorder, antimalarial drugs, and nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen. These medications can disrupt the immune system or directly affect skin cell growth, leading to flare-ups.

External Triggers:

• Skin Injury: Any injury to the skin, such as a cut, scrape, or sunburn, can trigger a flare-up in people with psoriasis. This phenomenon is known as the Koebner phenomenon. The injury disrupts the normal skin barrier and triggers an inflammatory response that can escalate into a psoriatic plaque.
  
  
• Infection: Infections, particularly bacterial infections like strep throat, can trigger psoriasis, especially guttate psoriasis. The body’s heightened immune response to the infection can spill over and affect the skin cells, leading to a flare-up.
  
  
• Weather: Cold and dry weather can worsen psoriasis symptoms. The colder temperatures and lower humidity can dry out the skin, making it more irritated and susceptible to flare-ups. People  with psoriasis often find their symptoms improve during warm, humid weather.
  
  
• Smoking and Alcohol: Smoking is a significant risk factor for developing psoriasis and can worsen existing symptoms. The chemicals in cigarettes can damage skin cells and contribute to inflammation. Excessive alcohol consumption can also exacerbate psoriasis by affecting the immune system and hindering its ability to regulate skin cell growth.
  
  
• Obesity: People with obesity are more likely to have severe psoriasis. Adipose tissue, or fat tissue, produces inflammatory molecules that can worsen psoriatic inflammation. Additionally, the increased skin folds in obese individuals can create a warm, moist environment that favors the growth of fungus, which can further trigger flare-ups.

 Psoriasis and Comorbidities

Psoriasis isn’t just a skin condition. Research has revealed a link between psoriasis and an increased risk of developing several other health problems. This connection seems to be rooted in the underlying chronic inflammation that characterizes psoriasis. 

Psoriatic arthritis is a specific type of arthritis that affects some people with psoriasis, occurring in around 30% of cases. The chronic inflammation driving psoriasis appears to extend to the joints in psoriatic arthritis, causing pain, stiffness, swelling, and joint damage.

People with psoriasis have a higher risk of developing Cardiovascular Disease (CVD), including heart attack and stroke. Chronic inflammation is again a common thread. Psoriasis may contribute to the buildup of plaque in arteries, a hallmark of CVD. Additionally, some medications used to treat psoriasis might elevate cardiovascular risk.

Metabolic syndrome is a cluster of conditions that includes high blood pressure, insulin resistance, abnormal cholesterol levels, and abdominal obesity. The chronic inflammation linked to psoriasis might disrupt insulin regulation and metabolism, potentially leading to metabolic syndrome.

Obesity is a risk factor for developing psoriasis, and people with psoriasis are more likely to be obese. The reasons for this two-way relationship are complex and likely involve a combination of genetic and inflammatory factors. Obesity can worsen psoriasis symptoms, and psoriasis itself might influence weight management.

People with psoriasis often have a higher risk of developing depression. The chronic itching, pain, and disfigurement caused by psoriasis can significantly impact quality of life and contribute to emotional distress and social isolation, potentially leading to depression. Additionally, some psoriasis medications might have mood-related side effects.

How is Psoriasis Diagnosed?

Diagnosing psoriasis usually involves a two-step process. The first step relies on gathering information about your medical background and a physical examination by a dermatologist. The second step might involve some additional tests depending on the specifics of your case.

During the initial consultation, the dermatologist will delve into your medical history. This includes any family history of psoriasis, as the condition has a genetic component. They will also ask about your symptoms, such as itching, burning, or pain. You’ll be asked to share any potential triggers you’ve noticed, like stress or certain medications, and details about any current medications you’re taking.

Following the discussion, a thorough physical examination is conducted. The dermatologist will pay close attention to the location, size, and appearance of any skin lesions you have. They’ll be looking for specific characteristics depending on the potential type of psoriasis. For example, they’ll check for the characteristic red, scaly plaques common in plaque psoriasis, or the presence of small, teardrop-shaped lesions suggestive of guttate psoriasis. The location of lesions can also be a clue, with inverse psoriasis affecting smooth areas like armpits or groin, and scalp psoriasis presenting as scaly patches on the scalp that might extend to the forehead or ears.

In most cases, the information gathered from the medical history and physical exam is sufficient for diagnosis. However, in some instances, additional tests might be needed for confirmation or to rule out other possibilities. These tests may include skin scrapings, where a small sample of skin cells is collected and examined under a microscope to differentiate psoriasis from fungal infections or eczema that can mimic its symptoms. In rare cases, if the diagnosis remains unclear after the initial steps, a biopsy might be performed. This involves extracting a small sample of affected skin for microscopic analysis in a lab to definitively identify psoriasis.

How is Psoriasis Treated?

Psoriasis, while not curable, has a range of treatment options available to manage symptoms and improve quality of life. The specific approach will depend on the severity and type of psoriasis you have, as well as your individual needs and preferences. Here’s a breakdown of the most common treatment methods:

1. Topical Treatments:

• These are often the first line of defense, particularly for mild to moderate psoriasis. They come in various forms like creams, ointments, lotions, and shampoos and target the affected skin directly.
  • Corticosteroids: These reduce inflammation and itching but should be used cautiously and as directed by your doctor to avoid side effects with long-term use.
  • Vitamin D Analogues: Synthetic forms of vitamin D that help slow skin cell growth.
  • Retinoids: Derived from vitamin A, they can help normalize skin cell growth.
  • Salicylic Acid: Loosens scales and promotes shedding of dead skin cells.
  • Coal Tar: Has anti-inflammatory and anti-itching properties.
  • Calcineurin Inhibitors: Newer medications that suppress the immune system in the skin, but require careful monitoring due to potential side effects.

2. Light Therapy (Phototherapy):

• Ultraviolet (UV) light exposure can be beneficial in some cases. There are two main types:
  • Ultraviolet B (UVB) therapy: Can be delivered at a doctor’s office or at home with a special light unit.
  • Psoralen plus Ultraviolet A (PUVA) therapy: Involves taking a medication (psoralen) that makes the skin more sensitive to UVA light, followed by exposure to UVA light in a controlled setting.

3. Systemic Medications:

• These are medications taken orally or by injection and work throughout the body for moderate to severe psoriasis or when other treatments are not effective.
  • Methotrexate: An immunosuppressant drug that slows down the growth of skin cells.
  • Cyclosporine: Another immunosuppressant drug, but with a higher risk of side effects.
  • Biologics: Targeted therapies that block specific molecules involved in the inflammatory process of psoriasis.

4. Lifestyle Modifications:

• Certain lifestyle changes can significantly improve psoriasis symptoms and overall well-being:
  • Maintaining a healthy weight: Obesity can worsen psoriasis.
  • Moisturizing regularly: Dry skin can exacerbate itching and discomfort.
  • Managing stress: Stress is a known trigger for psoriasis flare-ups. Relaxation techniques like yoga or meditation can be helpful.
  • Following a balanced diet: Some studies suggest a link between psoriasis and certain dietary factors. Avoiding processed foods, excessive sugar, and unhealthy fats may be beneficial.
  • Smoking cessation: Smoking worsens psoriasis and is bad for overall health.

5. Combination Therapy:

• In many cases, a combination of these treatment approaches might be used to achieve optimal results. Your dermatologist will develop a personalized treatment plan based on the severity and type of your psoriasis, your medical history, and your preferences.

What Medications are Most Often Prescribed for Psoriasis?

Psoriasis treatment medications come in various forms, targeting the condition from the outside in (topical) or working throughout the body (systemic). Here’s a breakdown of the most commonly prescribed medications for each category:

Topical Treatments: The First Line of Defense

For mild to moderate psoriasis, topical medications are usually the first line of defense. These medications come in various forms like creams, ointments, lotions, and shampoos, and they target the affected skin directly. Here are some of the most commonly prescribed ones:

• Corticosteroids: These medications are effective at reducing inflammation and itching. However, they should be used cautiously and exactly as directed by your doctor to avoid side effects, particularly with long-term use. Brand names can include hydrocortisone cream (Hycort), betamethasone dipropionate ointment (Diprolene), and clobetasol propionate cream (Temovate).
  
  
• Vitamin D Analogues: Synthetic forms of vitamin D that help regulate skin cell growth. They are often combined with corticosteroids for better efficacy. Calcitriol ointment (Calcitrex) and calcitriol solution (Vectical) are examples.
  
  
• Retinoids: Derived from vitamin A, retinoids can help normalize skin cell growth. They can be irritating to the skin, so careful use is necessary. Tazarotene cream (Tazorac) is a commonly prescribed retinoid for psoriasis.
  
  
• Salicylic Acid: This medication helps loosen scales and promotes shedding of dead skin cells, making the skin smoother.
  
  
• Coal Tar: Coal tar has anti-inflammatory and anti-itching properties. However, it can have a strong odor and stain clothes, so it might not be suitable for everyone. Coal tar shampoo (Ionil T) and coal tar ointment (various brands) are examples.
  
  
• Calcineurin Inhibitors: These are newer medications that suppress the immune system specifically in the skin. They can be effective, but careful monitoring by your doctor is required due to potential side effects. Tacrolimus ointment (Protopic) is a brand name example of a calcineurin inhibitor used for psoriasis.
  
  

Systemic Medications: For Moderate to Severe Cases

Systemic medications are typically reserved for moderate to severe psoriasis or when topical treatments aren’t effective. These medications work throughout the body to suppress the overactive immune response driving psoriasis. Some of the most commonly prescribed systemic medications include:

• Methotrexate: An immunosuppressant drug that slows down the growth of skin cells. It can have side effects, so regular blood tests are needed to monitor for potential issues.
  
  
• Cyclosporine: Another immunosuppressant drug, cyclosporine can be very effective but carries a higher risk of side effects compared to methotrexate. Due to this, it’s usually used for short periods or in severe cases.
  
  
• Biologics: These are targeted therapies that block specific molecules involved in the inflammatory process of psoriasis. Biologics are typically injected and have become a major advancement in psoriasis treatment, offering good efficacy with fewer side effects compared to traditional immunosuppressant medications. Some examples include adalimumab (Humira), ustekinumab (Stelara), and secukinumab (Cosentyx).