Keratolytic agents assist in removing scale or hyperkeratosis in patients with psoriasis or other dermatoses. A commonly used keratolytic agent is salicylic acid. It is usually prescribed in concentrations between 2 and 10 percent and should not be applied extensively on the body, especially in children, for fear of inducing salicylism (e.g., toxic effects marked by tinnitus, nausea and vomiting). Salicylic acid in concentrations of 5 to 10 percent compounded in petrolatum, acid mantle cream or even mid- strength topical corticosteroids can be used twice daily for several weeks at a time on thick keratotic plaques. Stronger concentrations of keratolytics (20 percent salicylic acid) can be applied for about two weeks to remove the thick scale to enable other topical therapies to better penetrate the skin. Urea-containing preparations and alpha-hydroxy acids, such as glycolic and lactic acids, are also effective keratolytic agents.