Psoriasis is a long-term inflammatory condition that results from a problem with the body's immune system. Skin changes and other symptoms can occur.
There are several types of psoriasis, but plaque psoriasis is the most common. The condition involves patches on the skin, which silvery scales cover. The patches, or plaques, can be itchy and painful.
The plaques have a well-defined edge and can appear almost anywhere on the body, but they typically affect the scalp, knees, elbows, and lower back.
The symptoms tend to come and go, worsening during times of flare and improving or disappearing during times of remission.
Scientists do not know what exactly causes psoriasis, but genetic and immune factors appear to play a role.
People with psoriasis may have specific genetic features that predispose them to the disease.
Psoriasis can run in families, but not everyone with these genetic features develops psoriasis.
The relevant genetic features may increase a person's risk of developing symptoms in certain circumstances, however. An infection, for example, may trigger psoriasis in a person who has a genetic predisposition.
A person can have genetic features that make them susceptible to psoriasis but not develop the condition. Nevertheless, exposure to certain triggers can cause symptoms to appear.
Possible triggers include:
Some people also report that changes in the weather, allergies, and dietary factors affect their psoriasis.
Some of these circumstances or factors can be triggers for the development of psoriasis and a flare when the condition becomes worse for a time.
Plaque psoriasis features pink plaques of skin with well-defined edges. They may be uncomfortable and itchy and may bleed and crack.
On black skin, the plaques may be darker in color rather than pink. Heavy white or silvery scales often cover the surface of the plaques.
Psoriasis plaques can occur anywhere on the body but are most likely to appear on the elbows, knees, lower back, and scalp.
Skin plaques are the hallmark symptom of plaque psoriasis, but psoriasis does not only affect the skin.
Other symptoms may vary between people, but they can include:
- pitting of the nails
- other nail changes
- joint pain
A flare is when symptoms appear or worsen, and they can last for several weeks or months. Between flares, the symptoms may improve or disappear. This cycle tends to repeat itself.
How does psoriasis affect black skin? Find out here.
Psoriasis is a multisystem disease that can affect many aspects of a person's life and health.
People with plaque and other types of psoriasis are also more likely to experience:
- other autoimmune disorders, including ulcerative colitis and Crohn's disease
- heart disease and high blood pressure
- features of metabolic disorder, such as obesity, high blood pressure, and diabetes
Several other health issues also appear to be more common in people with psoriasis than in those without the disease. Experts do not yet know what exactly links many of these conditions with psoriasis.
Current guidelines recommend people with psoriasis have regular screening for diabetes, lipid levels, and other health measures that may indicate cardiovascular or other health problems.
Doctors sometimes misdiagnose plaque psoriasis because the symptoms may resemble those of other conditions, including:
- seborrheic dermatitis
- pityriasis rosea
- Mycosis fungoides (cutaneous T cell lymphoma)
- lichen planus
- ringworm, also known as tinea
In the case of seborrheic dermatitis and psoriasis, there is a disorder known as sebopsoriasis that overlaps with them both.
Learn more here about conditions that have similar symptoms to plaque psoriasis.
A doctor can usually diagnose plaque psoriasis by looking at the skin and nails and examining someone's medical history.
Sometimes, a doctor will use a skin biopsy to confirm a diagnosis. They will take a small sample of skin to examine under a microscope. This procedure can help rule out other conditions.
When to see a doctor
Anyone who notices unusual changes in their skin should see a doctor.
Individuals with a diagnosis of psoriasis should follow their treatment plan and see their doctor if symptoms persist or worsen, or if treatment results in adverse effects.
There is currently no cure for plaque psoriasis, but many treatment options are available, depending on the individual and the severity of symptoms.
- topical treatments, including ointments, creams, and shampoos to relieve skin symptoms
- light therapy to relieve skin symptoms and possibly prevent flares
- laser therapy that targets specific skin patches
- corticosteroid injections to reduce severe inflammation
- systemic therapy
- biologic drugs
- lifestyle choices
Most people with mild symptoms can treat their psoriasis at home with topical treatments.
Topical treatments are often the first choice for managing plaque psoriasis.
Ingredients in topical treatments include:
- topical retinoids
- synthetic vitamin D
- salicylic acid
Applying creams and ointments that contain one or more of these ingredients can:
- reduce inflammation
- slow skin cell growth
- soothe the skin
- reduce dryness and cracking
- improve itching
Various topical treatments are available from a pharmacist or for purchase online, with or without a prescription.
It is best to check first with a doctor or pharmacist before choosing a topical treatment, as some may suit an individual better than others. In certain cases, there may not be enough scientific evidence to confirm that they are safe to use or work.
Some oral or injected medications that affect the whole body may help treat moderate to severe plaque psoriasis.
Examples of these systemic medications include:
The impact of a systemic therapy will depend on what it is, but the effects are likely to include reducing inflammation and changing how the immune system works. A doctor will monitor for any adverse effects that may occur.
These drugs affect the immune system and target the underlying cause of psoriasis. A range of biologics is available on prescription.
A doctor may prescribe one of these drugs if a person has moderate to severe symptoms of plaque psoriasis.
Phototherapy uses natural or artificial light to reduce symptoms.
The treatment may include:
- controlled exposure to sunlight
- exposure to UVB light in a light box
- PUVA, which combines medication with UVA exposure
Laser therapy aims to break up skin patches by targeting skin lesions directly.
Learn more here about excimer Xtrac laser therapy for psoriasis.
Skin-care tips that may help include:
- Taking a short bath or shower every day in warm but not hot water.
- Using coal tar or hypoallergenic products as a doctor or pharmacist recommends.
- Washing gently with the hands rather than scrubbing with a sponge to avoid irritation.
- Moisturizing with a thick hypoallergenic emollient within 5 minutes of bathing.
Other lifestyle tips include:
- avoiding alcohol and tobacco
- avoiding stress where possible
- getting enough sleep
People with psoriasis often have a vitamin D deficiency. While controlled sun exposure may improve symptoms, there is not enough evidence to support the use of vitamin D supplements for psoriasis.
A 2018 study noted that there is some evidence that using the following complementary or alternative remedies may help:
People should speak to their doctor first before trying any of these.
Plaque psoriasis is a common condition that people can often manage with topical treatments. If symptoms persist or become severe, other treatments are available that can help manage psoriasis.
Anyone who notices new or worsening skin changes or who starts to have joint pain or other symptoms should see a doctor.