Medical Dermatology

Psoriasis

Dr. Liew Hui Min

accredited consultant dermatologist

Psoriasis is a chronic autoimmune condition that causes skin cells to grow too quickly, resulting in thick, red, scaly patches. These plaques commonly appear on the elbows, knees, scalp, and lower back, but they can develop anywhere on the body. The condition occurs when the immune system mistakenly attacks healthy skin cells, leading to inflammation and an increased rate of cell turnover. Psoriasis is not contagious, and while it is a lifelong condition, its severity can vary, with flare-ups followed by periods of remission.

Symptoms Causes Types Diagnosis Treatment Prevention FAQ

Symptoms of Psoriasis

Psoriasis presents with a range of visible and physical symptoms, varying in severity from mild to severe. Common symptoms include:

Red, raised patches

Inflamed areas of skin covered with silvery-white scales, which may crack and bleed. These plaques can range in size from small spots to large areas across the body.
Dry, cracked skin

Affected areas become very dry, with cracks or splits that may bleed, particularly during flare-ups.
Itching and burning

Individuals may experience intense itching or burning sensations around the plaques. Scratching can aggravate inflammation and increase the risk of skin infections.
Thickened nails

Nail psoriasis leads to pitting, abnormal nail growth, discolouration, and, in severe cases, separation of the nail from the bed.
Scalp involvement

Psoriasis on the scalp appears as red patches with silvery-white scales, often extending beyond the hairline. This can lead to dandruff-like flaking and temporary hair loss in affected areas.
Joint pain and stiffness

Some people develop psoriatic arthritis, causing painful, stiff, and swollen joints. The severity can range from mild discomfort to debilitating pain that affects mobility.

Causes and Risk Factors

Psoriasis results from a combination of genetic predisposition and environmental factors that trigger an autoimmune response in susceptible individuals.

Genetic factors: A family history of psoriasis increases the likelihood of developing the condition. Many individuals with psoriasis have at least one affected family member. Certain gene variations related to immune function also contribute to the risk.
Immune system dysfunction: In psoriasis, T-cells (a type of white blood cell) mistakenly attack healthy skin cells, triggering inflammation and accelerating skin cell production, leading to the build-up of cells on the skin’s surface.
Environmental triggers: Infections, particularly streptococcal throat infections, skin injuries, certain medications, smoking, alcohol consumption, and vitamin D deficiency, can trigger psoriasis or provoke flare-ups in those already affected.
Stress: Both physical and emotional stress can contribute to the onset and exacerbation of psoriasis. Stress hormones can increase inflammation in the body, including the skin.
Obesity: A higher body mass index (BMI) is linked to an increased risk and severity of psoriasis. Fat cells release inflammatory substances, which may worsen the condition.

Types of Psoriasis

Plaque psoriasis

The most common form, characterised by raised, red patches covered with silvery-white scales. These plaques often appear on the elbows, knees, and scalp but can develop anywhere on the body.

Guttate psoriasis

Typically triggered by a bacterial infection, such as strep throat, guttate psoriasis presents as small, drop-shaped, red lesions with a fine scale. It commonly affects children and young adults.

Inverse psoriasis

This form appears as smooth, red lesions in skin folds, such as under the arms, in the groin, and around the genitals and buttocks. The lack of scaling distinguishes it from other types.

Pustular psoriasis

Characterised by white pustules surrounded by red skin, pustular psoriasis can be localised to certain areas, such as the hands and feet, or cover large areas of the body. It often causes severe discomfort.

Erythrodermic psoriasis

A rare and severe form, erythrodermic psoriasis causes widespread redness and shedding of the skin in large sheets. It can lead to severe itching, pain, and even complications like dehydration or infection. It requires immediate medical attention.

Nail psoriasis

Affecting the nails, this type causes pitting, thickening, discolouration, and in severe cases, nail separation from the nail bed. Nail psoriasis often occurs alongside other forms of psoriasis.

Psoriatic arthritis

This type involves joint pain, stiffness, and swelling, alongside the skin symptoms of psoriasis. It can lead to joint damage and disability if untreated.

Diagnostic Methods

Physical examination: The skin, scalp, and nails are examined to identify features of psoriasis, with attention given to lesion distribution, appearance, and severity. This helps differentiate psoriasis from other similar conditions.

Medical history assessment: Information on the onset, duration, and progression of symptoms is collected to identify potential triggers and patterns. Family history, past treatments, and medications that may worsen symptoms are also considered, assisting in diagnosis and treatment planning.

Skin biopsy: In some cases, a small skin sample is taken for microscopic examination. The tissue is examined for typical psoriasis changes, such as thickened skin layers and inflammation, helping to distinguish psoriasis from conditions like eczema or fungal infections.

Blood tests: Although no blood test can confirm psoriasis, certain tests can help rule out other conditions or detect complications, such as psoriatic arthritis. Blood tests also monitor potential side effects from medications.

Imaging studies: For joint symptoms, X-rays, ultrasound, or MRI scans may be used to assess psoriatic arthritis, detecting inflammation, bone changes, and damage to allow for early treatment and prevent permanent harm.

Treatment Options

Treatment options for psoriasis vary based on severity, ranging from topical treatments for mild cases to biologics and oral medications for more severe forms.

Topical therapies

For mild psoriasis, topical treatments like steroid creams and Vitamin D analogues are commonly used to reduce inflammation, thickness, and scaling of psoriatic lesions. These treatments effectively manage symptoms in less severe cases.

Phototherapy

In cases where topical and oral treatments are insufficient, phototherapy (ultraviolet light) is used to slow skin cell growth. This is particularly effective for moderate to severe psoriasis and can be combined with other treatments.

Oral immunosuppressants

For moderate psoriasis, oral immunosuppressants such as methotrexate and cyclosporine are prescribed to suppress the immune system’s overactive response, slowing the skin cell turnover that causes psoriasis.

PDE4 inhibitors

PDE4 inhibitors, such as apremilast, are oral medications that target specific enzymes involved in the inflammatory process. They help reduce symptoms of moderate to severe psoriasis, improving both skin and joint health.

Biologic therapies

For more severe cases, biologic drugs are used to target specific immune pathways causing psoriasis. Recent advances have introduced biologics with strong safety profiles, many of which also provide relief from psoriatic arthritis, improving both skin and joint symptoms.

Prevention and Management

While psoriasis cannot be fully prevented, managing symptoms and reducing flare-ups is possible. Identifying and avoiding personal triggers, such as stress, certain medications, or environmental factors, is key. Regular moisturising, especially after bathing, helps reduce dryness and scaling. Using gentle, fragrance-free products and avoiding harsh soaps can prevent irritation. Moderate sunlight exposure may benefit many patients, but sunburn should be avoided. Regular exercise, a healthy weight, limiting alcohol, and smoking cessation can improve symptoms and treatment effectiveness.

Frequently Asked Questions

Is there a cure for psoriasis?

There is currently no cure for psoriasis, as it is a chronic autoimmune condition. However, various treatments can control symptoms and help achieve long periods of clear skin. Psoriasis typically follows a relapsing-remitting pattern, with flare-ups alternating with periods of improvement.

Can diet impact psoriasis?

Diet can influence psoriasis, though its effects vary among individuals. Many find relief from anti-inflammatory diets that reduce processed foods, refined sugars, and fatty meats while increasing fruits, vegetables, whole grains, and omega-3-rich fish.

How does stress affect psoriasis?

Stress can trigger both the onset and flare-ups of psoriasis by increasing inflammation in the body. Stress hormones can promote inflammation, and stress-related behaviours, like poor sleep, smoking, or alcohol use, may further worsen symptoms. Managing stress through techniques like exercise, meditation, and adequate rest can help reduce flare frequency.

Dr Liew Hui Min

Dually Accredited Dermatologist In Singapore and the UK

Dr. Liew Hui Min is an accredited consultant dermatologist from the Ministry of Health and the General Medical Council UK.

Her clinical interest includes:

Paediatric Dermatology,
Women’s Dermatology,
General Adult Dermatology.

Having trained in major London Hospitals, Dr Liew returned to Singapore in 2014 as a Consultant at KK Women’s and Children’s Hospital (KKH) where she specialised in paediatric, women, obstetric and vulva dermatology. Currently, Dr Liew practices at HM Liew Skin & Laser Clinic located at Gleneagles Hospital.

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