Topical preparations containing α-hydroxy acids and closely related compounds were found to exert profound effects on epidermal keratinization in ichthyosis. Therapeutically efficacious compounds include citric acid, ethyl pyruvate, glycolic acid, glucuronic acid, 3-hydroxybutyric acid, 2-hydroxyisobutyric acid, lactic acid, malic acid, methyl pyruvate, pyruvic acid, tartaric acid, and tartronic acid. These materials appear to influence the process of keratinization per se, but do not seem to be keratolytic.
Van Scott EJ, Yu RJ. Control of Keratinization With a-Hydroxy Acids and Related CompoundsI. Topical Treatment of Ichthyotic Disorders. Arch Dermatol. 1974;110(4):586-590. doi:10.1001/archderm.1974.01630100046011