Topical salicylic acid in acne treatment

Salicylic Acid

Acne vulgaris is a common skin disorder affecting about 70%-80% of adolescents as well as young adults. It is characterized by both non-inflammatory and inflammatory lesions on the face and upper trunk of the patients. For most patients with mild to moderate comedonal or papulopustular acne, topical therapy is the most appropriate treatment option. Salicylic acid (1-5%) is a b-hydroxyacid that can be used as a topical peeling agent to treat mild comedonal acne in addition to topical retinoid therapy.

What is Salicylic Acid?

Salicylic acid is preferred to other commonly used traditional peeling agents. It is a component in various over the counter acne products including lotions, creams, alcohol based solutions and medicated pads. Salicylic acid is contained in a hydroethanolic formula at a 20%-30% concentration. This acid is a derivative of benzoic acid and represents a carboxy acid attached to an aromatic alcohol phenol. It is mild and works like a keratolytic agent i.e. it encourages the sloughing of dead skin cells. It is a safe and effective treatment for mild acne, oily skin, textural changes and post inflammatory hyper pigmentation and in people with darker skin.

How does Salicylic Acid work?

Salicylic acid is an excellent keratolytic agent exhibiting some degree of percutaneous absorption and functions by dissolving the intercellular cement that binds the epithelial cells together leading to the reduction in the corneocyte adhesion. Salicylic acid has a lipophilic character that facilitates the peeling of the top layer of skin and the opening of plugged follicles, which leads to a renewal of the skin cell replacement cycle. Thus, Salicylic acid has a strong comedolytic effect.

Comedones are formed due to excessive keratinization in the mid section of the follicular canal. A lipohhilic agent like salicylic acid goes in the middle of the sebaceous unit and prevents the formation of comedones. Salicylic acid affects the arachidonic acid cascade and has anti inflammatory properties also. Hence, it is useful in reducing both non-inflammatory as well as inflammatory acne lesions. Salicylic acid helps unclog pores to resolve and prevent lesions but cannot affect the secretion of sebum from the sebaceous gland or have any effect on the P.acnes bacteria.

Salicylic acid must be used continuously even after the acne lesions have been healed as a maintenance therapy, because if application is stopped the pores become clogged once again and there is renewal of acne formation.

How Salicylic acid should be used?

Absorption of salicylic acid in the skin is more efficient compared to other topical drugs. The time period for application of salicylic acid should be in proportion to the dose absorbed. How efficiently the absorbed salicylic acid works depends on the duration of skin contact and the medium of application. It has been seen that some salicylic acid ointment led to a 20%-25% of absorption. While most of the topical drugs are left on the skin surface for 8-12 hours, preparations containing salicylic acid should be taken off after a few minutes so as to reduce the amount of absorption. Preparations which have a concentration of .05%-10% of salicylic acid are recommended for use in acne treatment. However, in all non-prescription acne preparations, the concentration up to 2% of salicylic acid is permitted in the U.S. Salicylic acid can be used in case of children also.

It should be kept in mind that though systemic toxicity is a rarity with topical application, if the drug is applied to a large surface area of the skin for a long time, there may be occurrence of salicylate toxicity.

Salicylic acid is not to be taken orally as it leads to excessive stomach irritation.

Side effects associated with Salicylic acid usage

In all preparations where the concentration of salicylic acid is more than 2% there may be exfoliation of skin and discomfort. The most common side effect is dryness of skin which is usually mild. Adverse reactions are experienced when there is systemic use or if it is used over a large area for long. These reactions are toxic inner ear damage and hypersensitivity. Also patients using salicylic acid preparations should consult their doctor when the experience side effects like heavy breathing, dizziness, hearing impairment, lethargy, digestive disorders, and nausea. Salicylic acid is n FDA Pregnancy Category C drug so women who are pregnant should consult their doctors as this medicine can be absorbed through the skin.

Salicylic acid has been proven to significantly reduce acne severity and most patients report moderate to good improvement with this therapy. Salicylic acid peels can be used alongside traditional acne therapy to speed up resolution of the comedones and inflammatory papules. And its anti inflammatory character is also helpful for post inflammatory erythema. However, due to rapid and efficient percutaneous absorption of the drug, it is wise to take a cautious approach while using this drug.