Psoriasis

Psoriasis is a long-term condition in which the immune system drives skin cells to build up faster than usual, forming raised patches called plaques. The patches can itch, burn or crack, and they tend to come and go in flares. It is now understood as an inflammatory condition that can affect the joints and other parts of the body as well as the skin.

What psoriasis is, and what it is not

It is not contagious. You cannot catch psoriasis from someone else or pass it on by touch, and it is not caused by poor hygiene. It is also not only a skin problem: the same inflammation is linked to joint disease, and clinicians in Canada now ask about the joints as a standard part of the assessment.

Psoriasis also does not look the same on every skin tone. On lighter skin, plaques often appear red or pink with silvery scale. On darker skin they can look purple, brown or grey, which can make them harder to recognise. A Canadian consensus paper has identified gaps in psoriasis care for people with skin of colour, and that is one of the things current research is trying to close.

Signs and symptoms

• Raised, thickened patches of skin, often with scale
• Itching, burning or soreness in the affected areas
• Skin that cracks or bleeds, especially over joints
• Nail changes such as pitting, thickening, or the nail lifting from its bed
• Small drop-shaped spots that can appear after an infection, more often in children and young adults
• Joint pain, stiffness or swelling, which can signal psoriatic arthritis
• Flares that come and go, sometimes after stress, an infection or an injury to the skin

How much skin is involved, and where, differs greatly from person to person, and the same person can have quiet months followed by a flare.

What raises the risk

Some things cannot be changed:

• Family history: the Canadian Dermatology Association reports that about one third of people with psoriasis have at least one affected family member
• Genetic factors affecting immune signalling
• Age, with most cases developing in adulthood, while the drop-shaped form appears more often in childhood and early adulthood
• Certain infections, such as streptococcal throat infection, which can set off a flare

Others can often be worked on, usually with support from a health care team:

• Smoking
• Excess body weight and alcohol intake
• Stress, injury to the skin and certain medications, which some people find come before a flare

How psoriasis is diagnosed in Canada

Psoriasis is usually diagnosed by a family doctor, nurse practitioner or dermatologist based on how the skin, scalp and nails look and where the patches are. A skin biopsy is sometimes taken when the appearance is unclear, or to tell psoriasis apart from other skin conditions. Because psoriatic arthritis is common, clinicians also ask about joint pain, morning stiffness and swelling, and may refer you to a rheumatologist.

Treatment and day-to-day management

Clinical research for Psoriasis is enrolling. See the current studies ↓

Care in Canada is chosen according to how much skin is involved, which areas are affected, whether the joints are involved, and what else is going on with your health. Depending on your situation and what matters to you, a health care team may discuss:

• Topical treatments, including corticosteroids, vitamin D analogues and combination products
• Phototherapy, most often narrowband ultraviolet B, delivered in clinic settings
• Systemic oral medicines, including conventional immunomodulators and newer targeted oral small molecules
• Biologic medicines grouped by what they target, including TNF inhibitors, IL-12 and IL-23 inhibitors, IL-17 inhibitors and IL-23 inhibitors
• Care for associated conditions, including psoriatic arthritis, cardiovascular and metabolic risk, and mental health support

Access is not the same everywhere. Canadian reports document that biologic use varies with income, from 4% among people in the lowest income bracket to 14% in the highest, and coverage differs by province and territory. What suits one person will not suit another, and which of these applies to you is a decision for you and your own clinician. This page is not a recommendation about any of them.

When to talk to a doctor

• See a clinician for persistent scaly or thickened patches, scalp scaling that does not settle, or nail changes, so the condition can be identified and options discussed.
• Book an appointment promptly if you develop joint pain, morning stiffness lasting more than 30 minutes, or swelling of fingers or toes, since psoriatic arthritis is assessed and managed differently.
• Seek urgent care for widespread redness covering most of the body, for pustules with fever and feeling unwell, or for a rapidly worsening flare, as these need immediate assessment.

Why clinical research matters for psoriasis

It is still not established why psoriasis develops in some people, why response to the same treatment varies so widely between individuals, or how to predict who will go on to develop psoriatic arthritis. Canada has no national prevalence figure either: the strongest Canadian measurement comes from Ontario health administrative records and reflects 2015, and it does not match the national organisational estimate when scaled up. Canadian reports also document unequal access by income, and gaps in care for people with skin of colour. Research now under way includes new and comparative biologic targets, targeted oral small molecules, treat-to-target strategies aimed at limiting long-term cumulative impact, biomarkers to predict psoriatic arthritis, and work on diagnosis and severity assessment across the full range of skin tones.

Clinical studies are how those questions get answered. Taking part is voluntary, you give informed consent before anything begins, and you can stop at any time without affecting the care you get from your own doctor. Joining a study does not mean giving up your current treatment, and no one can tell in advance whether a study will help you personally.

Learn more from Canadian sources

• Canadian Dermatology Association: psoriasis
• Psoriasis Canada
• Canadian Skin Patient Alliance
• Overburdened: a report on the burden of psoriatic disease in Canada