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Medical Dermatology


What is psoriasis?

Psoriasis is a chronic inflammatory disease of the immune system. It mostly affects the skin and joints, but it also may affect the fingernails, the toenails, the soft tissues of the genitals and inside of the mouth. Psoriasis is a serious medical condition that affects approximately 7.5 million people in the United States. Psoriasis occurs in all age groups but is primarily seen in adults, with the highest proportion between ages 45 and 64. Approximately 25-30% of people with psoriasis experience joint inflammation that produces symptoms of arthritis. This condition is called psoriatic arthritis. Psoriasis and psoriatic arthritis can be associated with other diseases and conditions, including diabetes, cardiovascular disease, and depression.

About 90% of patients have the most common form of psoriasis, known as plaque psoriasis. It is characterized by patches of raised, reddish skin covered with silvery-white scale. Psoriasis is not contagious.

What causes psoriasis?

Psoriasis is an inflammatory immune system disorder. One third of cases run in families but research reports that multiple genetic abnormalities have been associated with psoriasis. It begins when certain immune system cells, called T-cells, cause inflammation and accelerate the growth of skin cells producing new skin cells within days rather than weeks.

Psoriasis can also be triggered by the environment, in situations of increased stress, certain infections, some medications, and by alcohol and tobacco consumption.

What are the symptoms?

The characteristic psoriasis plaques are thick, itchy and red with slivery scales that shed. The plaques develop on both sides of the body and are usually found on the knees, elbows, scalp, lower back, face, hairline, palms and soles of the feet. Studies report that about 50% of patients also have finger and/or toenail psoriasis. It may be confused with eczema which is intensely dry and itchy skin that usually develops in the backs of the knees and front of the elbows.

The second most common form is called guttate psoriasis. It is characterized by widespread small, red scaly spots on the arms and legs that develop weeks after a strep throat or viral infection. This type often begins in childhood or early adulthood and affects the body and limbs. It may go away on its own or develop into plaque psoriasis.

Other types:

  • Inverse psoriasis – Smooth, red patches that are sore located in the armpits, genitals, and buttocks.
  • Pustular psoriasis – pus-filled bumps usually on the hands and feet that are sore and painful. If widespread, this form of psoriasis can be life-threatening.
  • Nail psoriasis – changes in the fingernails and toenails causing dents, discoloration, and lifting because of the buildup of skin cells.

It is important to note that symptoms can be mild or severe. Discoloration of the affected skin is distressing, and the scales can shed onto clothing and furniture.

How is psoriasis diagnosed?

Your board-certified dermatologist will conduct a physical examination of your skin, inquire about your symptoms, and whether there are family members with this disorder. A biopsy of the skin may be taken to confirm the diagnosis, although this is not usually necessary.


There are many options to manage psoriasis but there is no cure.

Topical therapies

Topical treatments are helpful for mild to moderate psoriasis but do not tend to be effective for treating severe psoriasis, or psoriatic arthritis. Topical treatments can sometimes be used together with other medications. Topical corticosteroids and non-steroidal medications are available in many strengths and formulations.


Phototherapy is the controlled use of ultraviolet light. It may be recommended for people with moderate to severe psoriasis. Phototherapy may be combined with topical treatments or photosensitizing drugs in more severe and extensive psoriasis.

Systemic therapy

Patients with more severe and stubborn symptoms may require systemic therapy. Traditional systemic medications, either taken orally or via an injection, work throughout the body in a nonspecific manner to reduce symptoms of psoriasis. Biologic agents, also work throughout the body, target specific parts of your immune system that are implemented in psoriasis symptoms. In cases of more extensive psoriasis, topical agents may be used in combinations with phototherapy, or traditional systemic or biologic medications.

Despite its considerable effect on quality of life, psoriasis is under diagnosed and under treated. When you have concerns about a rash seek evaluation from a board-certified dermatologist at Phoenix Surgical Dermatology Group. Schedule a consultation to assure you receive the correct diagnosis and treatments that can help you restore your quality of life, self-image and confidence.

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