BOSTRIP: Biomarkers of Systemic Treatment Response in Psoriasis

Inclusion Criteria: * Male and female patients aged 18 - 80 years, body weight ≤ 180 kg * Dermatological diagnosis of psoriasis * Initiated therapy with TNFα-inhibitor agents (etanercept, adalimumab and infliximab)or fumaric acid ester (FAE) within the scope of routine patient care by treating physician * Signed informed consent from patient Exclusion Criteria: * Patients with evidence of any skin condition that would interfere with the evaluation of psoriasis * Use of systemic anti-psoriatic drugs such as steroids, retinoids, methotrexate, cyclosporine within 30 days of Visit 1 or used FAE or other any biologic agent such as etanercept, infliximab and adalimumab within 12 weeks prior to Visit 1 * Patients who are considered potentially unreliable or where it is envisaged the patient may not consistently attend scheduled study visits * Patients who are unable to complete a patient diary or complete questionnaires on paper * Patients with any other condition or prior/current treatment, which in the opinion of the investigator renders the patient ineligible for the study schedule * Pregnancy or breast feeding women * Women of child-bearing potential, defined as all women physiologically capable of becoming pregnant unless they use effective contraception during the study. Effective contraception is defined as either: use of established oral, injected or implanted hormonal