Salicylic acid is a beta hydroxy acid that works on psoriasis lesions through its anti-inflammatory and exfoliating properties. Salicylic acid has the ability to disrupt the cellular structures that hold the upper cell layers of the skin together. This leads to the exfoliation (known as a comedolytic effect) which helps prevent the pores from clogging with dead skin cells, and decrease plaque formation.
Salicylic acid is an organic acid that has been used for many years in the topical treatment of psoriasis. Salicylic acid is used as a keratolytic agent, which means it has an exfoliating or peeling effect. Its keratolytic effect occurs by dissolving the extracellular matrix and softening of the upper skin layer1 (stratum corneum). This promotes the shedding of psoriatic scales and reduces the scale build-up and softens the plaques2. This effect is achieved in concentrations up to 6%, whereas higher concentrations are destructive to the tissue1. Data on salicylic acid used alone on psoriatic plaques is limited.
Because of the keratolytic effect, salicylic acid is sometimes used as an adjunctive treatment that is believed to enhance the penetration of topical therapeutics2. For instance, a combination treatment including salicylic acid with a corticosteroid was shown to be more effective than the corticosteroid treatment alone in people with moderate plaque psoriasis following a 3-week study period3.
The concentration of an ingredient is important for its efficacy, and therefore products containing the same ingredient may not necessarily have the same effect as in the studies mentioned above.
Updated: July 2017