For many people, psoriasisskin plaques don’t improve significantly after topical treatment with ointments or creams. And, sometimes, too much skin is affected by psoriasis, making topical treatment impractical.
At the same time, systemic psoriasis drugs have more potential side effects. Knowing the benefits and risks of systemic psoriasis treatment can help you and your doctor make the right choice for your treatment.
Topical vs. Systemic Psoriasis Treatment
Topical therapies are any psoriasis treatment that’s applied on the skin. Absorption into the bloodstream and effects elsewhere in the body are minimal. Common topical treatments include:
Ultraviolet light (phototherapy) can also be focused only onto affected areas of skin.
Systemic psoriasis treatments, working on the entire body, often act on the immune system to reduce psoriasis activity over large areas of the body. These are used to treat moderate to severe psoriasis. Advanced psoriasis treatments include:
Phototherapy, or ultraviolet light treatment to the whole body.
While systemic psoriasis treatments are far more effective than topical creams, they also have more potential side effects and are more expensive.
Severity of Psoriasis Is Important
In considering systemic psoriasis treatment, consider how severe your psoriasis is. Doctors divide people with psoriasis according to how much skin is affected:
Mild-to-moderate or limited psoriasis: Less than 3% of total body surface is affected. (For reference, the palm of the hand is about 1% of total body area.)
Moderate psoriasis: 3% to 10% or more of body surface is affected.
Severe psoriasis: greater than 10% is affected.
A doctors’ rule of thumb: Limited psoriasis can be managed with topical therapies. For moderate-to-severe psoriasis, regularly applying topical creams to all the skin affected may be unrealistic. Most doctors recommend systemic psoriasis treatment for moderate-to-severe psoriasis.
Doctors also often recommend patients continue to use topical psoriasis ointments while taking system treatments. The combination leads to better results than either treatment used alone.