Psoriasis & Psoriatic Arthritis

Psoriasis is a chronic autoimmune condition that causes red, scaly patches of skin with well-defined borders. Commonly affected areas include the back of the elbows, knees, scalp, trunk and, occasionally, in the cleft between the buttocks. However, several different types of psoriasis exist and can cause very different distribution of the rash.  Psoriasis can be very mild, or it can be moderate or even severe. Even mild psoriasis can be very distressing for patients.

Psoriasis is known to affect around 2-5% of the population. Research has shown that that psoriasis is caused by the immune system mistakenly activating a type of white blood cell called a T cell. Once activated, the T cell triggers a reaction that causes skin cells to grow too quickly. Normal skin cells live for about one month, and then are shed from the outermost layer of the skin. With psoriasis, skin cells mature much more quickly, typically in 3-6 days. This pace is so rapid that the body is unable to shed the dead skin cells, and patches of red skin, typically with white overlying scale, develop.

There are many different sub-types of psoriasis, but the most common type is called plaque psoriasis. Approximately 80% of patients with psoriasis have plaque psoriasis. Plaque psoriasis causes patches of raised, reddish skin covered by white or silver-colored scale. The patches commonly occur on the elbow, knees and lower back/folds of the buttocks; however, they can occur anywhere on the skin.

Psoriatic arthritis is a specific type of arthritis that occurs in people with psoriasis. It is thought to occur in approximately 30% of patients with psoriasis. Several sub-types of psoriatic arthritis are known to exist.  The most commonly affected joints are the small joints in the hands and feet, but other joints can be affected, as well. Because the joint damage can be permanent, more aggressive treatment is recommended for patients with psoriatic arthritis.

Research has shown that psoriasis is associated with other serious health conditions, including heart disease, diabetes and depression. For this reason, your dermatologist will ask that you follow closely with your primary care physician. Closely monitoring your weight, blood pressure, cholesterol and monitoring for diabetes is now known to be very important.

Treatment:
While there is no cure for psoriasis, there are now a number of medications available that can very effectively manage psoriasis and psoriatic arthritis.

Treatment options include:
Topical medications: Various topical treatments, including topical steroids, vitamin D derivatives and other topicals can help manage mild disease.

Light therapy (phototherapy):
 This is done in a dermatologist’s office. Side effects include burns, freckling and premature aging of the skin. Narrowband ultraviolet radiation B (UVB) has been found to be the most effective form of phototherapy. Self-treating by using a tanning bed is never recommended. The beneficial effect of light therapy is attributed primarily to UVB. Tanning beds emit mostly UVA, not UVB. The American Academy of Dermatology, as well as the Center for Disease Control and Prevention, strongly discourage the use of tanning beds and sun lamps given that these devices are known to increase the risk of skin cancer and cause premature aging.

Laser therapy:
 Specific lasers, including excimer lasers and pulse dye lasers, can help to treat stubborn patches of psoriasis. This is not appropriate for patients with a large amount of psoriasis, however.

Oral medication:
 Several medications that suppress the immune system have been shown to improve psoriasis. Medications commonly used include methotrexate, retinoids (vitamin A derivatives) and cyclosporine.

Biologics
Biologics are the newest class of medications for the treatment of psoriasis and psoriatic arthritis.  Biologics are currently available in injectable or IV forms. Biologics frequently used for psoriasis and psoriatic arthritis include inflimimab (Remicaid), etanercept (Enbrel), adalimumab (Humira) and ustekinumab (Stelara). Additional biologics are currently in investigational trials and should be available in the near future. The addition of biologics to the market has been a very exciting advancement for patients with psoriasis and psoriatic arthritis. Like other medications that act on the immune system, biologics can increase the risk of infection. Certain cancers, blood disorders and serious rare nervous system disorders have also been reported in patients taking biologics. However, these side effects thankfully are quite rare. The use of biologics is a special area of expertise for Dr. Fromm, as she has served as an investigator in several clinical trials for biologics that are now available on the market and some that are still in phase 3 clinical trials.