The skin in psoriasis: assessment and challenges.

The coexistence of psoriasis arthritis (PsA) and psoriasis vulgaris in about 20% of patients with psoriasis leads to a need for rheumatologic-dermatologic team work. We summarise the role of dermatologists in assessment of the skin in psoriasis. Chronic plaque psoriasis must be differentiated from other subtypes such as generalised pustular psoriasis (GPP) or palmoplantar pustulosis (PPP). Therapeutic management is based on the evaluation of the disease severity. Quantitative scoring of skin severity includes calculation of the Psoriasis Area and Severity Index (PASI), body surface area (BSA) as well as the Dermatology Life Quality Index (DLQI). These scoring systems do not replace the traditional dermatologic medical history and physical examination of the patient. The skin should be examined for additional skin diseases; moreover, patients should be monitored for comorbidity, most importantly PsA and cardiovascular comorbidity.