Psoriasis risk factors and triggers

What psoriasis is

Psoriasis is a chronic (long-lasting) disease in which the immune system becomes overactive and skin cells multiply too quickly. Patches of skin become scaly and inflamed, most often on the scalp, elbows or knees, but other parts of the body can be affected (NIAMS). Normally skin cells take about a month to rise to the surface; in psoriasis this happens in just days (MedlinePlus).

Scientists do not fully understand what causes psoriasis, but they know it involves a mix of genetics and environmental factors (NIAMS).

Who gets psoriasis

Anyone can get psoriasis. It is more common in adults than in children, and it affects men and women equally (NIAMS). MedlinePlus says it usually occurs in adults and sometimes runs in families (MedlinePlus).

Risk factors

• Family history and genes. Many people with psoriasis have a family history of the disease. Researchers have pinpointed some of the genes that may contribute, and many of them play a role in how the immune system works (NIAMS).

NIAMS lists these outside factors that may increase the chances of developing psoriasis (NIAMS):

• Infections, especially streptococcal and HIV infections.
• Certain medicines, such as drugs for treating heart disease, malaria or mental health problems.
• Smoking.
• Obesity.

If you smoke, the quit smoking help check covers the help available to quit.

Triggers that can make symptoms worse

Psoriasis symptoms come and go, with flares followed by times when you feel better (NIAMS). MedlinePlus lists these as things that make symptoms worse (MedlinePlus):

• infections
• stress
• dry skin
• certain medicines

NIAMS names stress and skin injuries as common triggers, and says managing them can help keep symptoms under control (NIAMS). Some types have their own triggers (NIAMS):

• Guttate psoriasis, which usually appears in children or young adults, is often triggered by an upper respiratory infection such as strep throat.
• Pustular psoriasis can be triggered by medicines, infections, stress or certain chemicals.
• Inverse psoriasis, in skin folds, can be made worse by rubbing and sweating.
• Erythrodermic psoriasis, a rare but severe form, can be triggered by a bad sunburn or certain medicines such as corticosteroids.

Conditions that come with psoriasis more often

NIAMS says having psoriasis carries the risk of other serious conditions (NIAMS):

• Psoriatic arthritis, a chronic arthritis with pain, swelling and stiffness of the joints and of the places where tendons and ligaments attach to bones. Stiff, swollen or painful joints, neck or back pain, or Achilles heel pain are reasons to see your doctor soon, because untreated psoriatic arthritis can lead to irreversible damage.
• Cardiovascular events, such as heart attacks and strokes. Our heart disease risk factors guide covers those risks with its own sources.
• Mental health problems, such as low self-esteem, anxiety and depression.

People with psoriasis may also be more likely to get certain cancers, Crohn's disease, diabetes, metabolic syndrome, obesity, osteoporosis, uveitis (inflammation of the middle of the eye), liver disease and kidney disease (NIAMS).

Signs to bring to a doctor

Common symptoms include patches of thick, red skin with silvery-white scales that itch or burn; dry, cracked skin that itches or bleeds; thick, ridged, pitted nails; and poor sleep (NIAMS). Psoriasis can be hard to diagnose because it can look like other skin diseases, and a doctor may need to look at a small skin sample under a microscope (MedlinePlus).

Common questions

Is psoriasis genetic?

Partly. Many people with psoriasis have a family history of it, and some genes linked to it have been found, but environmental factors also play a part (NIAMS).

Which risk factors can I change?

Genes and family history cannot be changed. Smoking and obesity are on the NIAMS list of factors that may raise the chances of psoriasis, and stress and skin injuries are common triggers (NIAMS). Some medicines are also listed, but do not stop a medicine without talking to your clinician.

How is it treated?

Treatment depends on the type and how severe it is. Mild psoriasis can often be treated with creams or ointments, while moderate and severe psoriasis may need pills, injections or light treatment (NIAMS).

Also see rheumatoid arthritis risk factors and lupus risk factors, other immune-related diseases.