Quick answer. Psoriasis is a common, chronic, immune-mediated (autoimmune) skin condition in which skin cells turn over too fast, producing thick, scaly, red or pink plaques most often on the elbows, knees, scalp and lower back. It is not contagious and is not caused by poor hygiene. Symptoms tend to flare and settle with triggers such as stress, infections, skin injury, smoking and alcohol, and some people also develop psoriatic arthritis (joint pain and swelling). It cannot be cured but is very manageable: mild disease responds to topical treatments, while moderate-to-severe disease is treated with phototherapy and systemic medicines or biologics prescribed and monitored by a dermatologist, such as at the National Skin Centre.
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Psoriasis is one of the more common long-term skin conditions seen in Singapore, affecting an estimated 1-2% of the population, with around 40,000 people living with it according to the Psoriasis Association of Singapore. It is a chronic, immune-mediated condition that causes thick, scaly patches of skin – it is not an infection, is not contagious, and is not a result of poor hygiene. While psoriasis cannot be cured, modern treatment can control it very well, and good control makes a real difference to comfort, confidence and overall quality of life. This guide explains the symptoms, common triggers and the treatment options available, and when to see a doctor.
At a glance
| Severity | Treatment approach | Notes |
|---|---|---|
| Mild | Emollients/moisturisers, topical steroids, vitamin D analogues (calcipotriol), coal tar | Applied to the skin; suits most people, who have mild disease |
| Moderate | Phototherapy – UVB light (or PUVA in selected cases) | Given in a clinic over a course of gradually increasing doses |
| Moderate-to-severe | Conventional systemics, e.g. methotrexate (also acitretin, ciclosporin) | Oral/injected; needs dermatologist supervision and blood-test monitoring |
| Moderate-to-severe / resistant | Biologic medicines targeting TNF-alpha or interleukins (IL-17, IL-23) | Injectable, highly effective; prescribed and monitored by a dermatologist |
| With joint symptoms | Assessment for psoriatic arthritis; systemics or biologics as appropriate | Tell your doctor about joint pain/swelling; early treatment protects joints |
What is psoriasis?
Psoriasis is a chronic, immune-mediated (autoimmune) skin condition. Normally skin cells take about 28 days to grow and shed, but in psoriasis the immune system speeds this up so that cells reach the surface in just 3-7 days. The excess cells pile up, producing the thick, scaly plaques that are typical of the condition.
Two points are worth stressing because they are often misunderstood. First, psoriasis is not contagious – you cannot catch it or pass it on through touch, sharing food or using the same pool. Second, it is not caused by poor hygiene. It arises from a combination of genetic and environmental factors that cause the immune system’s T-cells to react against healthy skin. About one in three people with psoriasis has a family member with the condition. In Singapore it can appear at any age but commonly starts in the 20s-30s or 50s-60s.
Symptoms and how to recognise it
The most common form is plaque psoriasis: raised, red or pink patches covered with silvery-white scales. Plaques often appear symmetrically and most commonly affect the elbows, knees, scalp and lower back, though they can occur anywhere, including the ears and the genital area. Patches may be itchy or feel sore, and the skin can crack.
Other features to look out for:
- Nail changes – pitting (tiny dents), thickening, discolouration or the nail lifting from the bed.
- A flare-and-remit pattern – psoriasis tends to come and go, with periods of clearer skin between flare-ups.
- Joint symptoms – some people with psoriasis develop psoriatic arthritis, which causes joint pain, stiffness and swelling. If you have any joint aches or swelling, mention it to your doctor, as early treatment helps protect the joints.
Common triggers and flare-ups
Psoriasis is influenced by triggers that can set off or worsen a flare. Knowing your own triggers and managing them is an important part of keeping the condition under control. Common triggers include:
- Stress and anxiety
- Infections, especially streptococcal throat infections (a classic trigger for guttate psoriasis)
- Skin injury – cuts, scratches, sunburn or friction can trigger plaques at the site (the Koebner phenomenon)
- Certain medications, such as lithium and antimalarial drugs
- Smoking, which raises the risk and the severity of psoriasis
- Alcohol, particularly in excess
- Weather – cold, dry conditions can worsen symptoms for some people
Being overweight is also linked to more severe disease, so a healthy lifestyle supports better skin control.
How psoriasis is diagnosed
Psoriasis is usually a clinical diagnosis – a doctor or dermatologist can often recognise it from the appearance and distribution of the plaques and the nail changes. In cases that are less clear-cut, a skin biopsy (taking a small sample of skin for examination) may be done to confirm it. Your doctor may also ask about joint symptoms to screen for psoriatic arthritis, and review your general health, as psoriasis is associated with other conditions discussed below.
Treatment options by severity
Treatment is matched to how severe the psoriasis is, usually following a stepped approach. Psoriasis cannot be cured, but the right treatment can clear or greatly reduce plaques and keep them under control.
Mild disease – topical treatments. Most people have mild psoriasis and do well with creams and ointments applied to the skin: moisturisers/emollients to soften scale, topical steroids, vitamin D analogues (such as calcipotriol/calcitriol), and coal tar preparations.
Moderate disease – phototherapy. When topicals aren’t enough, controlled ultraviolet B (UVB) light therapy delivered at a clinic can be very effective, given in gradually increasing doses over a course of sessions. PUVA (psoralen plus UVA) is another option in selected cases.
Moderate-to-severe disease – systemic treatments and biologics. For more extensive or stubborn psoriasis, a dermatologist may prescribe conventional systemic medicines such as methotrexate (also acitretin or ciclosporin), or modern biologic medicines – injectable drugs that precisely target the immune signals driving psoriasis (for example TNF-alpha or interleukins such as IL-17 and IL-23). These medicines are powerful and need to be prescribed and monitored by a dermatologist, including blood tests, to use them safely.
Living well and when to see a doctor
Psoriasis is a lifelong condition, but it is very manageable, and good control improves day-to-day comfort and quality of life. It is also linked with other health conditions – including metabolic problems (such as obesity and diabetes) and cardiovascular disease – so looking after your overall health matters: keeping a healthy weight, staying active, not smoking and moderating alcohol all help both your skin and your general wellbeing.
See a doctor if you have a persistent rash with scaly patches, if your skin condition is spreading, painful or affecting your sleep, work or mood, or if you notice joint pain or swelling. Your GP can start treatment and refer you to a dermatologist – such as at the National Skin Centre (NSC), which runs a dedicated psoriasis service – if your psoriasis is moderate-to-severe or not responding to first-line treatment.
Related guides
- Best Dermatology Clinics in Singapore — our editorial shortlist
- dermatology clinics directory
- Rosacea treatment
- Hives (urticaria)
- Fungal skin infections
Sources
- National Skin Centre (NSC) – Psoriasis, Health Library
- Dermatological Society of Singapore – Psoriasis: Causes, Types and Treatment
- HealthXchange.sg (SingHealth) – Psoriasis Causes and Prevention
- 2023 Guidelines on the Management of Psoriasis by the Dermatological Society of Singapore, Annals Academy of Medicine Singapore
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