Reviewed by: HU Medical Review Board | Last reviewed: July 2016. | Last updated: January 2022
What are plaques?
Psoriasis is an autoimmune condition that can cause different types of symptoms to appear on the skin. Plaques are the most common symptom experienced by people with psoriasis. Of the more than 7.5 million people who have been diagnosed with psoriasis in the United States, between 80% and 90% have plaque psoriasis.
Plaques are patches of skin that have a very dry, thickened texture and are raised higher than the surrounding skin. These patches are usually inflamed and reddish in color and can become covered with a layer of silvery scales on the surface1.
Plaques can feel very itchy, sore, and painful. They sometimes crack and bleed. When scratched or scraped, tiny spots of blood can appear on the plaque. These spots are called the Auspitz sign, and their presence is one of the signs that healthcare providers use when making a diagnosis of plaque psoriasis2.
Plaques usually begin as patches that are very small (about the size of a pinhead), which grow in size to cover larger areas of skin. During a flare-up, different patches can combine to form larger areas of plaque. Some people have plaque patches that are the shape of a ring, with healthy skin in the center encircled by a wavy, thickened and scaly border3.
Psoriasis plaques can develop anywhere on the body, and they usually appear on the same parts of opposite sides of the body. Some of the most common places where plaques occur are4:
What causes plaques to develop?
Plaques develop as the result of inflammation caused by an overactive immune system. This inflammation causes the body to produce new skins cells more quickly than older skin cells can be shed naturally. The new skin cells push the older ones up to the surface of the skin, where they build up and cause plaques to develop1.
How are plaques treated?
There is a range of options for treating the symptom of plaques, the most common being topical treatments and a type of treatment called phototherapy or light therapy. Many people find using a combination of different treatments to be effective.
Topical treatments are medicines that are applied directly to the area of skin affected by the plaque in the form of a lotion, cream, gel, liquid, or shampoo. Healthcare providers usually recommend that patients with milder psoriasis first try topical treatments to treat their plaques1.
Some topical treatments can be purchased over-the-counter (OTC), such as coal tar and salicylic acid. Coal tar works by helping to reduce the growth of excess skin cells that cause plaques, and is available in different strengths and forms. Treatments containing coal tar can be applied to the skin in a gel or ointment, or added to a bath as a liquid. People with psoriasis plaques on the scalp may find relief using a shampoo that contains coal tar. While coal tar products can be effective for many people, some people dislike this type of treatment because it has a strong smell, can be messy to apply, and can sometimes irritate the skin. It can also stain clothes, sheets, towels, and light-colored hair.
Other types of OTC treatments include3:
- Salicylic acid, which helps encourage the shedding process and lift scales to soften the plaques
- Aloe Vera
- Zinc pyrithione
Other types of stronger topical treatments require a prescription, such as topical corticosteroids. These work by reducing inflammation and affect the how quickly new skin cells that are produced. Other types of prescription topical treatments for treating plaques include5:
- Vitamin D analogues, such as calcitriol
- Vitamin A analogues (also called retinoids), such as tazarotene
Light therapy (or phototherapy) is a type of treatment in which the plaques are exposed to a specific type of light, which is absorbed into the skin and can help to relieve symptoms. Phototherapy can take place either in a healthcare provider’s office or in the patient’s home using special equipment. Treatment with phototherapy is often combined with topical treatments or systemic drugs called retinoids3.
For people with more severe plaques, healthcare providers may recommend treatment with systemic or biologic medicines that affect the way the immune system functions. They are designed to reduce inflammation and the symptoms, such as plaques, that inflammation causes.
Tips for managing plaque symptoms
Identifying and avoiding your personal psoriasis triggers can help to prevent flare-ups of plaques. Examples of triggers are skin injuries, infections, smoking, or sunburn. Stress is a trigger for many people, which can be lessened by using relaxation techniques or getting support from other people living with the condition, through a support group or online community1.
Many people with psoriasis find that using thick lubricant moisturizers or oils can provide relief for their psoriasis. Although they do not treat the cause of the symptoms directly, they work as a barrier to seal in moisture, soothe the skin, and reduce itching, cracking and scaling. Taking a daily bath in lukewarm water is helpful for some people, especially if they use additives such as bath oil, salts, or colloidal oatmeal6.
Getting a small amount of sun exposure every day on the affected skin can also improve plaques for people with mild or moderate psoriasis. However, it is very important not to get too much sun, which can cause a symptom flare up and increase the risk of skin cancer over time7.