As nails are not included in the general measures of disease severity (such as Psoriasis Area and Severity Index [PASI]), the Nail Psoriasis Severity Index (NAPSI) will be used to assign a score of nail psoriasis. The scalp, though being involved in the general measures of disease severity (e.g. PASI), represents only 4-5% of the body surface and is therefore poorly represented. Psoriasis Scalp Severity Index (PSSI) will be used to quantify the intensity of scalp psoriasis and its changes during the study. The association between general skin and localized nail and scalp, and changes in quality of life in response to adalimumab therapy will also be examined.