Beta-hydroxy acid peels

Beta hydroxy acid peels with pK around 3... 

Salicylic acid is a beta hydroxy acid. Glycolic acid is an alpha hydroxy acid, as are lactic acid, citric acid, and many others. Hydroxy acids are compounds that are both alcohols and acids at the same time. Hydroxy acids are used as chemical peeling agents. Alpha hydroxy acids can make the skin more sensitive to ultraviolet light by removing the skin s protective outer layers. Some alpha hydroxy acids ... 

Salicylic acid (ortho hydroxybenzoic add) is a beta hydroxy acid agent. It is a lipophilic compound which produces desquamation of the stratum corneum via removal of intercellular lipids [3] (see salicylic acid section). Given its keratolytic effects, it has become an increasingly popular superficial peeling agent. Salicylic acid peels induce injury via thinning or removal of the stratum corneum. In addition, salicylic acid potentially enhances the penetration of TCA. 

Different agents have been studied and depicted effectual in achieving a superficial depth peel. Among these, preferred for use are alpha-hydroxy adds (AHAs), beta-hydroxy acid (BHA), Jessner s original and modified solutions, and trichloroacetic acid (TCA). 

Salicylic acid is a lipophilic beta-hydroxy acid which is used as a peeling agent, compounded as 20-40% solution with ethanol. It is a hydroxyl derivative of benzoic acid and represents a carboxylic add attached to an aromatic alcohol, phenol. It is a white crystalline powder derived from willow bark, winter green leaves, and sweet birch [15]. 

A large number of combination peels are in the market which combine various alpha-hydroxy acids and also with beta-hydroxy acids. There are other proprietary peels, the exact composition of which is not known. There are hardly any randomized controlled studies on these in Asian patients. There are concerns about their stability and efficacy. Some are made for home use. A comparative study on 44 Indian patients with acne which had two groups, one receiving 35% glycolic acid peels and the other 20% salicylic acid-10% mandelic acid peels for six sessions at 2-weekly intervals, found salicylic-mandelic peel more efficacious for active acne and postacne hyperpigmentation [24]. Mandelic acid penetrates less but in the combination with salicylic acid has a beneficial role in postinflammatory hyperpigmentation. 

It is becoming common for beta hydroxy acid (BHA) peels to be used instead of the stronger alpha hydroxy acid (AHA) peels due to BHA s ability to get deeper into the pore than AHA. Studies show that BHA peels control oil, acne as well as remove dead skin cells to a certain extent better than AHAs due to AHAs only working on the surface of the skin. 

These include 10-15% trichloroacetic acid (TCA), alpha-hydroxy acid (AHA), beta-hydroxy acids such as salicylic acid, topical tretinoin, and one to two coats of Jessner s solution [14% resorcinol, 14% salicylic acid, 14% lactic acid, and ethanol). These peels penetrate the stratum corneum and possibly the upper layers of the stratum spinosum. Because of the very superficial depth of pene-... 

Chemical peeling agents are classified as keratolytics or protein denaturants. Keratolytics [alpha-hydroxy acids, beta-hydroxy acids) are primarily used for superficial, exfoliative procedures whereas the protein denaturants [trichloroacetic acid [TCA) and phenol) can be used for superficial, medium-depth, and deeper peels. This chapter will focus on modified TCA and phenol peel solutions. 

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