Moderate to severe psoriasis

Psoriasis can be mild, moderate or severe. Three percent to 10 percent of the body affected by psoriasis is considered to be a moderate case. More than 10 percent is considered severe. The palm of the hand equals 1 percent of the skin. However, the severity of psoriasis is also measured by how psoriasis affects a person's quality of life. Psoriasis can have a serious impact on an individual’s daily activities even if it involves a small area, such as the palms of the hands or soles of the feet. 

Treating moderate to severe psoriasis usually involves a combination of treatment strategies. Besides topical treatments, your doctor may prescribe light therapy/phototherapy and/or systemic medications. Light therapy/phototherapy involves regularly exposing the skin to light, and systemic medications are prescription drugs administered orally or by injection that work throughout the body.