Psoriasis causes red, scaly patches on the scalp, torso, and extremities in approximately 3% of the population. 30% of patients with psoriasis have a positive family history and 10-20% have co-existent psoriatic arthritis. Psoriasis is caused by a defect in the immune system which allows tumor necrosis factor to cause excessive skin turn over. Localized psoriasis is easily controlled with topical cortisone ointments, tar ointments, topical vitamin D-3, or UV light treatments. Widespread psoriasis is best controlled with systemic medication such as methotrexate or injections of “biologicals” such as Enbrel.