le who suffer from the skin disease psoriasis are at an increased risk for cancer, according to new research. Specifically, study authors found patients with psoriasis had a nearly three-fold increased rate of lymphoma. Psoriasis is a common skin disease that affects about 1 percent to 2 percent of the population. Patients with psoriasis have patches of thickened, red and scaly skin, usually on the torso or arms that can be painful and disfiguring. Lymphoma is a group of cancers that affect the lymph tissues found mainly in the lymph nodes and spleen. Previous research has found an association between psoriasis and lymphoma. Doctors from the University of Pennsylvania studied whether the rate of lymphoma in patients with a history of psoriasis is different from the rate of lymphoma in patients without psoriasis. Included in the study was a random sample of patients 65 years or older who were registered with a general practitioner. The research included 2,718 patients with psoriasis and 105,203 patients without psoriasis. Researchers kept track of who was diagnosed with lymphoma during a median follow up of 46 months. During the study period, researchers identified 276 lymphomas. Researchers say the patients with psoriasis were nearly three times more likely to be diagnosed with lymphoma than healthy participants. Furthermore, patients 65 years or older who had psoriasis developed an additional 122 lymphomas per 100,000 patients annually. After reviewing records, researchers found all the patients with psoriasis who had lymphoma were treated with medications consistent with psoriasis treatment. While researchers conclude there is an association between psoriasis and lymphoma, they feel additional research needs to be done to determine if this association is related to psoriasis severity, psoriasis treatment or an interaction between these risk factors.