What is psoriasis?

Psoriasis is a chronic skin disorder that presents with localized plaques of thick and scaly skin. In most patients, psoriasis affects the skin around the knees, elbows and scalp. Psoriasis has a variable course with waxing and waning of the symptoms. There are some people with very mild psoriasis on their nails who may not even know they have it. Others have severe psoriasis that can be disabling. In some cases, the symptoms may not appear for years and then suddenly appear when the weather is cold. There is unfortunately no cure for the disorder. The available treatments all help reduce the intensity of symptoms. Overall, the quality of life of patients with psoriasis is diminished because of the skin appearance. Many people become isolated and withdrawn because of their disease.

Who develops psoriasis?

Psoriasis can occur in people of all ages, both genders and affects all races. The diagnosis of psoriasis is usually made in those in their 30s. Recent studies indicate that people who develop psoriasis are also more prone to developing heart disease, diabetes and high cholesterol levels. Psoriasis is a common skin disorder that affects nearly 3% of the US population. The disorder is most common in Caucasians and less frequently seen in African Americans.

What causes psoriasis?

The cause of psoriasis is not known but it is suspected that some type of genetic defect that affects the immune system may be responsible. It is believed that a malfunction in the immune system leads to an increased production of the outer layer of skin while the older, dead skin is not rapidly removed. This leads to the development of thick plaques so typical of psoriasis. Psoriasis does run in families and so if someone in your family has the disorder, chances are that you will also develop it. Psoriasis is not contagious and you cannot acquire it from anyone else.

What can trigger psoriasis?

There are some people who have psoriasis that has not yet been triggered and if one is able to identify it, the disorder can be avoided. Some triggers for psoriasis include:

How many types of psoriasis exist?

There are several types of psoriasis which include the following:

Does psoriasis affect the joints?

Psoriasis does affect the joints in at least 30% of individuals. In some individuals with psoriasis, there may only be joint involvement with no signs of skin involvement. Psoriatic arthritis can affect both the small and large joints of the body. The joints most commonly affected include the hands, ankle, and knees. Unlike osteoarthritis, psoriatic arthritis is much more destructive and deforming.

When does psoriasis present?

Psoriasis first presents after the age of 30 and most people see the skin changes before joint involvement. Psoriasis can also affect the nails in a few individuals, which is difficult to treat. Psoriasis usually presents with small reddish bumps on the skin that slowly merge to form thick plaques over the elbows, scalp and knees. The lesions are itchy but not painful. Nail psoriasis can present with tiny depressions or large yellow discolorations that eventually lead to separation of the nail. In patients with pustular psoriasis, there may be small bumps filled with pus and these patients are usually ill and have a fever. Psoriasis of the scalp may look like dandruff with dry flakes, silvery patches and red skin. As the disease progresses some people may develop a burning sensation, soreness and itching.


The diagnosis of psoriasis is made from the history of presentation and physical exam. In very rare cases, a skin biopsy may be performed to confirm the diagnosis.

Psoriasis treatment

Psoriasis is usually treated by skin doctors, general physicians and rheumatologists. Over the years many treatments have been developed to treat psoriasis but the ideal treatment depends on the type of psoriasis, extent of disease and experience of the treating healthcare provider. There is no one medication that works in everyone and all medications have some side effects. Prior to treatment, the healthcare provider will discuss the pros and cons of each treatment. To minimize side effects, some of the drugs are rotated every 6-12 months. The treatment of psoriasis is divided into three categories:

In general, for psoriasis that only involves small areas of skin, topical creams and sprays may be safe to use and are effective. The topical agent is applied on skin and includes medications like corticosteroids, moisturizers, vitamin D creams, retinoids (tazarotene), coal tar, and topical immunomodulators like tacrolimus. In patients with moderate to severe disease that involves large areas of skin topical products are usually not effective. In such cases one may require oral medications, ultraviolet light, and some of the newer agents. Common oral agents include use of acitretin, methotrexate, cyclosporine, and apremilast. Individuals who have psoriasis that involve the joints usually require oral medications to prevent progression of the joint disease. The newest medications to treat psoriasis are the biological agents that work by suppressing the immune system. Available biological agents include Humira, Remicade, and Enbrel. Some of the agents can be self-administered at home but others are given in the doctor’s office as an intravenous infusion. Since the biological agents are relatively new, all patients are closely monitored for infections (e.g. tuberculosis) and potential development of cancer. Biological agents are costly and may not be covered by all insurance plans.

Role of light therapy

Light therapy is one of the oldest treatments for psoriasis. Today several artificial sources of light have been developed for home treatment. One can even use natural sunlight for treating psoriasis. Regular exposure to the sun can clear psoriasis in some patients. However it is important to protect the unaffected skin from sun exposure with the use of sunscreens.

Is there a psoriasis diet?

Many individuals with psoriasis are overweight and are prone to developing diabetes and heart disease. Thus, it is highly recommended that one exercise regularly, eat a healthy diet consisting of fruits and vegetables, and maintain a healthy weight. Overall, obese patients tend to respond poorly to treatment compared to lean individuals.

What are complications of psoriasis?

People who develop psoriasis are at a risk for developing the following complications:

Is it possible to prevent psoriasis?

Psoriasis appears to be a genetic disorder and cannot be prevented at this time. However, one can take several measures to improve the appearance of the skin and prevent flare-ups.  One should take daily baths, use ample moisturizer, expose skin to small amounts of sunlight, avoid excess alcohol, discontinue smoking and take steps to reduce stress.