Psoriasis

What is Psoriasis?

Psoriasis is a common autoimmune skin condition that causes your body to produce skin cells too quickly in an attempt to repair perceived skin injury or inflammation. This results in thick, scaly, red plaques that often itch, burn or sting.

These plaques typically show up on the scalp, elbows, knees and lower back. But they can appear anywhere on the body. Psoriasis is not contagious, but it is a chronic condition that can come and go throughout life.

Types of psoriasis

Psoriasis can appear in several forms. The type you have often determines what your skin looks like and which treatments may be most effective:

• Plaque psoriasis – the most common type. Plaque psoriasis appears as raised red rashes covered with silvery-white scales. They are commonly found on the scalp, elbows, knees and back.
  
• Guttate psoriasis – guttate psoriasis is more common in children and teenagers. They appear as small, red, drop-like spots, usually triggered by infections like strep throat.
  
• Pustular psoriasis – pustular psoriasis shows up as white pustules on red, inflamed skin, but is not caused by infection. It often affects the hands, feet, but may also cover large areas of the body in severe cases.
  
• Inverse psoriasis – inverse psoriasis affects skin folds like the armpits, groin, under breasts or around the genitals. The lesions appear shiny, smooth, red and are often worsened by sweat or friction.
  
• Erythodermic psoriasis – erythodermic psoriasis is a rare and severe form of psoriasis characterised by widespread inflammation covering large areas of the body, often more than 90% of the skin surface. The lesions appear as red, flaky or shedding skin, often accompanied by itching, swelling and pain.

What causes Psoriasis?

Psoriasis develops when the immune system becomes overactive, mistakenly attacking healthy skin cells and speeding up the skin cell turnover process. This leads to a buildup of skin cells on the surface, causing the thick scaly plaques seen in psoriasis. Inflammation also plays a key role, which is why symptoms often include redness, swelling and itching.

Common triggers for flare-ups include:

Internal triggers

• Certain medications
• Hormonal changes
• Infections, especially strep throat
• Stress

External triggers

• Alcohol consumption
• Cold weather or dry air
• Skin injuries, cuts, scrapes or sunburn
• Smoking

What are the symptoms of Psoriasis?

Psoriasis symptoms can vary from mild to severe, and common symptoms include:

Cutaneous symptoms

• Dry, cracked skin that may bleed
• Red, thickened plaque with silvery or white scales
• Itching, burning or stinging sensation

Extracutaneous symptoms

• Eye inflammation, such as conjunctivitis or uveitis
• Joint pain or swelling (psoriatic arthritis)
• Nail changes such as pitting, discoloration or thickening

Who is at risk of developing Psoriasis?

Certain factors can make some individuals more susceptible to developing psoriasis. This includes:

• Age-related factors – the skin condition tends to develop most commonly between the ages of 15 to 30 years old and 50 to 60 years old. These age windows are often when immune and hormonal changes are more pronounced.
• Genetic predisposition — individuals with a family history of psoriasis are significantly more likely to develop the condition themselves, especially those with early-onset disease.
• Hormonal factors – hormonal shifts during puberty, pregnancy or menopause may influence the onset of psoriasis or trigger flare-ups. These changes can affect the immune function and skin cell regeneration.
• Infections – illnesses, especially strep throat,can set off flare-ups. This is a common trigger for guttate psoriasis in children and young adults.
  
• Metabolic and immune-related conditions — such as obesity, high blood pressure and type 2 diabetes. These comorbidities are more common in people with psoriasis and may contribute to more severe disease due to systemic inflammation.
  
• Medications — certain drugs (like beta-blockers, antimalarials or lithium) can trigger or worsen psoriasis in some patients.
  
• Environmental triggers — relevant in Singapore’s climate. While psoriasis is not caused by the environment, sudden weather changes, infections or skin injuries (like cuts or sunburn) can trigger flare-ups in predisposed individuals.
  
• Lifestyle factors — including smoking, alcohol use and chronic stress. These habits are known to worsen inflammation in the body and are linked to increased psoriasis severity and frequency of flare-ups.

What is the link between Psoriasis and the Metabolic syndrome?

Psoriasis is increasingly recognised as a systemic inflammatory disease. This means it affects the body beyond the skin. One of the key associations identified in recent years is its link to the metabolic syndrome.

The Metabolic syndrome refers to a group of conditions that increase the risk of heart disease, stroke and type 2 diabetes. These include:

• Abnormal cholesterol or triglyceride levels
• Central obesity (excess fat around the waist)
• Elevated blood sugar
• High blood pressure

Studies have shown that individuals with moderate to severe psoriasis are more likely to develop metabolic syndrome compared to those without psoriasis. The connection lies in chronic low-grade inflammation.

In psoriasis, the immune system is constantly activated, releasing inflammatory compounds that not only affect the skin. It may also contribute to insulin resistance, fat accumulation and blood vessel dysfunction. This shared inflammatory pathway suggests that psoriasis and metabolic syndrome are biologically linked, not just coincidentally seen together.

Because of this connection, people with psoriasis may face a higher risk of cardiovascular disease and should be regularly screened for metabolic health issues. Lifestyle changes such as maintaining a healthy weight, eating a balanced diet, managing stress and staying physically active are important not only for skin health but also for long-term overall wellbeing.

How is Psoriasis diagnosed?

Psoriasis is often diagnosed by a dermatologist based on clinical presentations and symptoms. Other tests are rarely required unless the symptoms or diagnosis are inconclusive.

Psoriasis can be diagnosed via:

• Physical examination – a dermatologist can often make a diagnosis based on your symptoms and how your skin looks. They will also ask about your medical history, family history, and any past or ongoing skin issues. Common questions may include:
  
  
  • When did the symptoms first appear?
  • What triggers your psoriasis?
  • What home remedies or treatments have you tried?
  • Do you have family members with similar skin conditions?
    
    
• Skin biopsy – If necessary, a small sample of skin may be taken and examined under a microscope. This allows for detailed evaluation of skin cell changes, helping to confirm the diagnosis and rule out other skin conditions.

How is Psoriasis treated?

Treatment of psoriasis varies according to the severity of the disease. In mild cases, topical creams and ointments are recommended to manage symptoms and reduce skin dryness. In more serious cases, a dermatologist may recommend light therapy or systemic medications.

Topical treatments

Topical treatments are the first-line therapies indicated for psoriasis; these include:

• Moisturisers – keeping the skin well moisturised improves the skin’s barrier function and prevents dehydration of the skin.
  
• Topical corticosteroids – topical corticosteroids work by reducing and modulating the inflammation associated with psoriasis. Corticosteroids are also meant to be used for short-term relief, such as during psoriasis flares. Long-term use of corticosteroids can lead to skin atrophy, characterised by the thinning of the skin.
  
• Topical vitamin D – vitamin D analogue calcipotriol is a common medication used for treating psoriasis. While the exact mechanism of action is not well understood, calcipotriol is believed to target the inflammatory and proliferative pathways that cause psoriatic plaques. Calcipotriol is also often combined with steroid medications.
• Coal tar preparations – this treatment helps reduce scaling, itching and inflammation. It is available in creams, ointments and medicated shampoos. 
• Salicylic acid – this keratolytic agent softens and removes thick and scaly plaques. This allows other treatments like corticosteroids or vitamin D analogues to work more effectively. It is often used on stubborn or heavily scaled areas.

Light therapy 

Light therapy or phototherapy is commonly indicated for the treatment of psoriasis, especially if a large body surface area is affected.

These include:

• Psoralen with ultraviolet A radiation (PUVA) – PUVA involves the use of a medication called psoralen, a light-sensitive drug which is activated when exposed to UVA radiation.
  
• Narrowband ultraviolet B radiation (NBUVB) – NBUVB is a common treatment for various skin conditions such as psoriasis, vitiligo and atopic dermatitis. The procedure involves exposure to light from a narrow range of wavelengths (311 nm – 313 nm). The treatment is generally preferred over PUVA due to lower risks of side effects, such as gastrointestinal upset, cataract and skin cancer.
  
  

Systemic treatments

Systemic treatments are commonly given in extensive cases of psoriasis, often involving the nails and psoriatic arthritis. Common medications include:

• Methotrexate – Methotrexate is an immunosuppressive medication often given to patients with autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus and psoriasis. Methotrexate is meant to be taken as a single weekly oral dose, but injections are also available.
  
• Systemic retinoids – Acitretin is a systemic retinoid used in the management of psoriasis. Just like other retinoids, acitretin treats psoriasis by targeting skin cell proliferation. Common side effects of systemic retinoids can include dry skin, hair loss, high cholesterol and liver toxicity.
  
• Cyclosporine – this is a calcineurin inhibitor, which works to treat psoriasis via immunosuppression, similar to methotrexate. 
• Apremilast – an oral medication that works by targeting specific enzymes involved in inflammation. This helps to reduce the overactive immune response seen in the skin condition.

Biologic treatments 

Biologic treatments are a newer type of medication used for moderate to severe psoriasis. They work by targeting specific parts of the immune system that are overactive in psoriasis.

Most biologics are made from proteins, such as monoclonal antibodies and are given as injections. They block certain immune signals, like:

• Tumour necrosis factor (TNF) – such as adalimumab, infliximab, etanercept, certolizumab.
  
• Interleukins (IL-12, IL-17, IL-23) – such as ustekinumab, guselkumab, risankizumab, ixekizumab and brodalumab.

By targeting these immune pathways, biologics can reduce inflammation and help clear the skin and reduce flare-ups.

It’s important to note that several treatments for psoriasis are not safe for use during pregnancy. If you’re planning to conceive or have recently given birth, please inform your dermatologist so that a suitable treatment can be prescribed for your safety and your baby’s.

Summary

Psoriasis is a chronic, immune-driven skin condition that causes thick, red, scaly plaques. It can affect not just the skin, but also the nails, joints and eyes in some people. Although it is a long-term condition, with the right treatments, most people can achieve clear or nearly clear skin. There is a range of effective treatments available to help reduce symptoms, prevent flare-ups and improve your overall quality of life.

If you are experiencing ongoing symptoms or your psoriasis is affecting your daily routine, it may be time to consult a dermatologist for a personalised treatment plan. Schedule a consultation with us today for a detailed diagnosis and personalised treatment plan.