Localized Psoriasis Vulgaris

A 72-year-old man presents with skinlesions and nail abnormalities. Erythematous,sharply defined, demarcatedpapules and rounded plaquescovered by silvery micaceous scaleare noted on the elbows, knees, andscalp. Involved areas appear to be bilaterallysymmetric. Localized psoriasisvulgaris is diagnosed.(Case and photograph courtesy of Drs Sonia Arunabhand K. Rauhila.)What therapy would you offer?A REVIEW OF THE OPTIONSLocalized psoriasis vulgaris ofthe extensor extremities usually istreated with topical agents, such ascorticosteroids and/or tar, calcipotriene,and tazarotene, alone or incombination with natural sunlight.UV-B therapy may be recommendedfor patients whose lesions fail to respondto local measures.Many practitioners prefer theconcurrent use of a topical corticosteroidand either the topical vitaminD analog calcipotriene or the topicalretinoid tazarotene. Combinationtherapy is more effective than treatmentwith a single agent and can decreasethe risk of adverse reactions.Usually, an ultrapotent topicalcorticosteroid, such as betamethasonedipropionate or clobetasol propionate,is applied twice daily for 2weeks. Thereafter, the frequency ofapplication may be reduced fromtwice to once daily for 2 to 4 weeksand then discontinued while calcipotrieneis introduced once daily andthen increased to twice daily.Alternatively, after the first 2weeks of twice-daily application, thecorticosteroid may be applied onweekends only and the calcipotrieneused twice daily on weekdays. These treatment regimens provide promptrelief of the signs and symptoms ofthe disease. They also offer safemaintenance therapy without the adverseeffects of prolonged topical corticosteroiduse, such as skin atrophy,telangiectasia, and tachyphylaxis.A single daily application of tazaroteneis generally prescribed forlocalized disease in combination withonce-daily application of a mediumstrengthtopical corticosteroid, suchas betamethasone valerate or mometasonefuroate. Tazarotene lessens therisk of corticosteroid-induced atrophyand telangiectasia, and the corticosteroidreduces the irritation that candevelop from tazarotene use. A recentstudy showed that 2 weeks of combinationtherapy with tazarotene gel,once daily, and calcipotriene ointment,twice daily, was as effective astwice-daily application for 2 weeks ofan ultrapotent topical corticosteroidointment.²Coal tar, salicylic acid, and anthralinare other topical therapies thatare used in this setting. These preparations are particularly appropriatefor the treatment of thick, scaling psoriaticplaques. Because coal tar andsalicylic acid often need to be compounded,and coal tar and anthralincan be messy to apply, they are prescribedless frequently than corticosteroids,calcipotriene, and tazarotene.A new formulation of anthralin,which requires a shorter skin contacttime, minimizes staining and cutaneousirritation when unabsorbedmaterial is removed with cool or lukewarmwater without soap.CASE 1:APPROACH AND OUTCOMECombination therapy with a topicalcorticosteroid and calcipotrieneointment significantly improved thepatient's skin condition. He refusedtherapy for the nail manifestations.