An example of psoriasis on a person's arm across the elbow and forearm

What is Psoriasis?

Psoriasis is a chronic, non-contagious, skin condition in which skin cells grow too quickly, resulting in thick, white or red “plaques” of skin to form. In people without psoriasis, the skin cells grow gradually and flake off about every 4 weeks. As this occurs, new skin cells grow to replace the outer layers of skin as they shed. When an individual is afflicted with psoriasis, new skin cells move rapidly to the surface of the skin in days rather than weeks. This gives the appearance of the thick skin “plaques.” Plaques range in size, and most often appear on the knees, elbows, scalp, hands, feet, and lower back. Psoriasis can sometimes spread and lead to inflammation of the joints, which is referred to as psoriatic arthritis. Approximately 10-15% of people with psoriasis have psoriatic arthritis. Psoriasis is most common in adults, but can affect children as well.

The exact cause of psoriasis is unknown, but most doctors believe it occurs when the immune system overacts, causing inflammation and flaking of the skin. Approximately 30% of individuals with psoriasis have at least one member of the family with psoriasis as well. 


There is currently no known cure for psoriasis. However, there are many available treatment options. At the Institute of Dermatology & Aesthetics, Dr. Katsnelson will help you determine which method is best for you. Treatment aims to slow the rapid growth of skin cells and reduce inflammation.

  • Topical Medication:

    Treatment for mild psoriasis, or only a few plaques, is usually treated with prescription creams, ointments, solutions and lotions. Mild psoriasis of the scalp can be treated with prescription shampoos, solutions and oils.  Topical medications might include vitamin D compounds, corticosteroids, or retinoids.

  • Phototherapy:

    Another treatment for psoriasis is phototherapy. During phototherapy, the affected areas are briefly exposed to intense ultraviolet B light (UVB). UVB treatment is completed 2 to 3 times a week, and when used in combination with medicine such as calcipotriene, is quite effective. 

  • Oral Medication:

    When topical medications and phototherapy do not effectively treat moderate to severe psoriasis, an oral (by mouth) medication may be prescribed.  These drugs can have side effects, such as weakening the immune system, which is why they are generally reserved for more severe cases.

  • Biologics:

    Biologics are medications similar to the proteins made by the body. They block the harmful response of the body’s immune system that causes psoriasis. Biologics are an option for some patients who cannot use other treatments and have moderate to severe psoriasis. These drugs can have side effects, such as suppressing the immune system. Dr. Katsnelson will help determine if this is an option for treating your psoriasis.


There is no way to prevent psoriasis, but you may be able to reduce flare-ups and improve symptoms by abiding by the following guidelines:

  • Treat infections promptly. For example: Strep throat, in particular, can cause a type of psoriasis (guttate psoriasis) to appear suddenly, especially in children.
  • Try to minimize your stress level.  Stress can make psoriasis worse.
  • Follow gentle skin care instructions provided by Dr. Katsnelson.