Psoriasis

What is it?

According to the NIAMS: a chronic (long-term) disease in which the immune system becomes overactive and skin cells multiply very rapidly. MedlinePlus describes it as a skin disease that causes thick red patches with silvery scales that itch or hurt, usually appearing on the elbows, knees, scalp, back, face, and palms and soles. The NHS describes it as a common condition that cannot be cured but for which treatments are available to control its symptoms, and it is not contagious.

Its types according to the NIAMS: plaque (the most common: raised red patches with silvery-white scales), guttate (small red dots in children and young adults), pustular (pus-filled blisters on red skin), inverse (smooth red patches in skin folds), and erythrodermic (rare and severe: red scaly skin over most of the body). This page does not cover specific prevalence figures, but the NIAMS states it is more common in adults than in children.

Causes

According to the NIAMS: it results from a mix of genetics and environmental factors, and is immune-mediated, with immune cells producing molecules that stimulate rapid skin cell turnover; many patients have a family history. MedlinePlus explains that skin cells that normally take about a month to rise to the surface do so within days. The NHS states that the likelihood increases if a family member has it.

Risk factors

Factors and triggers according to the NIAMS: some infections (such as streptococcal bacteria and HIV), certain medicines, smoking, obesity, stress and skin injury, and sunburn (in the erythrodermic type). The NHS adds alcohol, pregnancy and sunlight. MedlinePlus mentions infections, stress, dry skin and some medicines.

Symptoms

According to the NIAMS: thick red skin patches with silvery-white scales that itch or burn, dry cracked skin that may bleed, thick ridged and pitted nails, poor sleep quality, and joint symptoms when there is psoriatic arthritis. Symptoms alternate between flares and remissions. The NHS states that patches are often 1 to 2 cm, look pink or red on light skin and grey on dark skin, and may leave dark marks after they clear.

How is it diagnosed?

According to the NIAMS: examination of the skin, scalp and nails, and questions about the medical and family history, and a skin biopsy may be taken for microscopic examination to rule out other conditions. MedlinePlus says it can be hard to diagnose because it resembles other skin diseases.

Treatment

The treatment categories usually used are listed here; this is not a prescription. The doctor chooses the plan according to each person's condition; do not change any medicine or dose without a specialist.

Treatment categories in the NIAMS (chosen by the doctor according to severity and condition): topical treatments (corticosteroids, vitamin D derivatives, retinoids, coal tar, anthralin, PDE4 inhibitors, AhR activators), antimetabolites, oral retinoids, biologic response modifiers, immunosuppressants, oral PDE4 and TYK2 inhibitors, and ultraviolet light therapy. The NHS mentions emollients, topical steroids, tar, phototherapy and systemic medicines.

Self-care steps according to the NIAMS: moisturising the skin with lukewarm baths and thick moisturisers, reaching a healthy weight and following a Mediterranean diet, quitting smoking and cutting down on alcohol, getting a little sun under medical guidance, identifying and avoiding personal triggers, and seeking psychological support or support groups.

Follow-up

According to the NIAMS the disease affects work, sleep and daily life, and quality of life improves with coordinated care and symptom control with the medical team; there is currently no cure. This page does not cover specific follow-up intervals.

Complications

According to the NIAMS and MedlinePlus: psoriatic arthritis, heart problems (heart attacks and strokes), and psychological problems (anxiety, depression and low self-esteem). MedlinePlus also mentions links with diabetes, metabolic syndrome, obesity, osteoporosis, inflammatory bowel disease (Crohn's), uveitis, liver and kidney disease and some cancers. The NHS mentions metabolic syndrome (diabetes, heart and vascular disease and deep vein thrombosis) and Crohn's disease.

Psoriatic arthritis according to the NIAMS: progressive inflammation of the joints and of the points where tendons and ligaments attach to bone; most people with it have psoriasis at diagnosis, joint pain may precede skin symptoms in some, and it usually appears about 7 to 10 years after skin symptoms begin. Its symptoms: joint stiffness, pain and swelling, fatigue, sausage-like swelling of the fingers, nail changes, and eye inflammation (uveitis). Early treatment is linked with better outcomes and less damage. MedlinePlus states that the joints and skin are not always affected together, and that rheumatologists (for the joints) and dermatologists (for the skin) care for the condition.

Prevention

This page does not cover a proven way to prevent psoriasis from appearing. The NIAMS recommends avoiding personal triggers (stress, cold, injuries, certain medicines and infections), managing weight, and quitting smoking to ease flares.

Living with it

According to the NIAMS and MedlinePlus: the disease is long-lasting and may continue for life with symptoms that come and go, and managing triggers helps control it. The NHS stresses that it is not contagious and is not passed on by contact.

Common questions