Psoriasis keratolytic agents

Sahcyhc acid USP, EP, and other pharmacopeia grades are used medically as antiseptic, disinfectant, antifungal, and keratolytic agents. Sahcyhc acid is formulated in lotion or ointment formulations for the treatment of dandmff, eczema, psoriasis, and various parasitic skin diseases. Because the keratolytic property of this aromatic acid has use in the safe removal of dead skin cells from the surface of healthy skin, the acid is used in concentrated sahcyhc acid solutions or suspensions to remove warts and corns. In more dilute form, sahcyhc acid preparations have found use in dandmff and eczema treatment. Sahcyhc acid has been considered and found effective by the Advisory Committees to the FDA in various over-the-counter (OTC) dmg regulated uses. Among these are acne products, dermatitis, dry skin, dandmff and psoriasis products, and foot care products (24). 

Keratolytic agents such as salicylic acid are often added to bath oil or shampoos (typically 3% to 4%) for scalp psoriasis.10 Salicylic acid can also be added to topical corticosteroid preparations to enhance steroid penetration (salicylic acid breaks down keratin). 

Propylene glycol is an effective keratolytic agent for the removal of hyperkeratotic debris. It is also used in combination with salicylic acid in the treatment of ichthyosis, psoriasis, keratosis pilaris and hypertrophic lichen planus. 

Its topical use lies mainly in the treatment of psoriasis, as a keratolytic agent to descale plaques (1-20% ointment). Salicylism is the term used to describe the toxicological state that occurs following percutaneous absorption of salicylic acid (Von Weis and Lever 1964). Intoxication depends largely on the total body area over which the salicylic acid is applied (Brubacher and Hoffman 1996). Formerly, salicylic acid also had a reputation as an anti-mycotic (3% in Whitfield ointment). Contact allergy was reported (Goh and Ng 1986). 

Urea is a hydrating agent (a hydrotrope) used to treat scaling conditions such as psoriasis, ichthyosis, and other hyperkeratotic skin conditions. Applied in a water-in-oil vehicle, urea alone or in combination with ammonium lactate hydrated stratum corneum and improved barrier function when compared to the vehicle alone in human volunteers in vivo [45], Urea also has keratolytic properties, usually when combined with salicylic acid for keratolysis. The somewhat modest penetration-enhancing activity of urea probably arises from a combination of increasing stratum corneum water content (water is a valuable penetration enhancer) and through the keratolytic activity. 

Antipsoriatic agents are used to treat psoriasis, a serious chronic skin condition characterized by scaly pink patches. A number of agents may be used in treatment, but there is no cure. KERATOLYTic (desquamating) AGENTS are used extensively, including coal tar, dithranol, etretinate, ichthammol and salicylic acid also retinoids (see below) and corticosteroids. 

---