Localized Psoriasis Vulgaris

A 72-year-old man presents with skin lesions and nail abnormalities. Erythematous, sharply defined, demarcated papules and rounded plaques covered by silvery micaceous scale are noted on the elbows, knees, and scalp. Involved areas appear to be bilaterally symmetric. Localized psoriasis vulgaris is diagnosed. (Case and photograph courtesy of Drs Sonia Arunabh and K. Rauhila.)What therapy would you offer?A REVIEW OF THE OPTIONS Localized psoriasis vulgaris of the extensor extremities usually is treated with topical agents, such as corticosteroids and/or tar, calcipotriene, and tazarotene(, alone or in combination with natural sunlight. UV-B therapy may be recommended for patients whose lesions fail to respond to local measures. Many practitioners prefer the concurrent use of a topical corticosteroid and either the topical vitamin D analog calcipotriene or the topical retinoid tazarotene. Combination therapy is more effective than treatment with a single agent and can decrease the risk of adverse reactions. Usually, an ultrapotent topical corticosteroid, such as betamethasone(dipropionate or clobetasol( propionate, is applied twice daily for 2 weeks. Thereafter, the frequency of application may be reduced from twice to once daily for 2 to 4 weeks and then discontinued while calcipotriene is introduced once daily and then increased to twice daily. Alternatively, after the first 2 weeks of twice-daily application, the corticosteroid may be applied on weekends only and the calcipotriene used twice daily on weekdays. These treatment regimens provide prompt relief of the signs and symptoms of the disease. They also offer safe maintenance therapy without the adverse effects of prolonged topical corticosteroid use, such as skin atrophy, telangiectasia, and tachyphylaxis. A single daily application of tazarotene is generally prescribed for localized disease in combination with once-daily application of a mediumstrength topical corticosteroid, such as betamethasone valerate or mometasone(furoate. Tazarotene lessens the risk of corticosteroid-induced atrophy and telangiectasia, and the corticosteroid reduces the irritation that can develop from tazarotene use. A recent study showed that 2 weeks of combination therapy with tazarotene gel, once daily, and calcipotriene ointment, twice daily, was as effective as twice-daily application for 2 weeks of an ultrapotent topical corticosteroid ointment.² Coal tar(, salicylic acid(, and anthralin are other topical therapies that are used in this setting. These preparations are particularly appropriate for the treatment of thick, scaling psoriatic plaques. Because coal tar and salicylic acid often need to be compounded, and coal tar and anthralin can be messy to apply, they are prescribed less frequently than corticosteroids, calcipotriene, and tazarotene. A new formulation of anthralin, which requires a shorter skin contact time, minimizes staining and cutaneous irritation when unabsorbed material is removed with cool or lukewarm water without soap.CASE 1:APPROACH AND OUTCOMECombination therapy with a topical corticosteroid and calcipotriene ointment significantly improved the patient's skin condition. He refused therapy for the nail manifestations.