Psoriasis is a chronic inflammatory skin disease. Associated comorbidities or risks may include psoriatic arthritis, obesity, depression, smoking, diabetes, hyperlipidemia, an increased risk of cardiovascular disease with myocardial infarction, or an increased risk of lymphoma. The clinical presentation of psoriasis can range from the more common red scaling elevated plaques on the elbows, knees, or scalp to the less common superficial pustules scattered on the palms or soles, or in rare cases wide-spread pustules on the body. More specifically, the clinical spectrum of psoriasis includes the plaque, guttate, small plaque, inverse, erythrodermic, and pustular variants. The determinants of the clinical severity of psoriasis, the risk of comorbidities, and the quality of life of a psoriatic patient are influenced by multiple factors. At the minimum, these include variations in the quality and type of psoriasis, the quantity of skin involved, and the distribution of skin lesions (including special areas such as the scalp, nails, face, intertriginous regions, and palmoplantar surfaces). Objective measures used to quantify the severity of psoriasis, including the body surface area involved, Physician's Global Assessment, Psoriasis Area and Severity Index, and quality of life measures, are all assessments that can be useful in guiding approaches to management and therapeutics. In this paper, we review the clinical spectrum of psoriasis, the differential diagnoses, measures and determinants of severity, and the recommendations on when to refer a patient to a specialist in psoriasis. We also briefly review the comorbidities, and note the importance of referring the psoriatic patient to the internist/general practitioner for evaluation and management for these comorbidities.

To define genes associated with the pigmentary disorder vitiligo, gene expression was compared in non-lesional melanocytes cultured from three vitiligo patients and from three control melanocyte cultures by differential display. A basic local alignment search tool search did not reveal homology of six differentially expressed cDNA fragments to previously identified expressed sequence tags; thus, one was used to screen a melanocyte cDNA library. The underlying VIT1 gene maps to chromosome 2p16. The 3' portion of the VIT1 message is complementary to the 3' end of hMSH6 mRNA, enabling the formation of RNA-RNA hybrids, which may interfere with G/T mismatch repair function. Moreover, the aligned cDNA sequence revealed an open reading frame identical to a hypothetical protein expressed in brain, with a similarity to Drosophila calmodulin, and containing a zinc-finger motif partially identical to N-recognin. Expression of ORF mRNA was confirmed for multiple skin cell types, suggesting its importance for skin physiology.

Bexarotene gel appears to be safe, tolerated by most patients, with useful therapeutic activity in chronic severe hand dermatitis.