Table of Contents
Salicylic Acid (SA)
Salicylic acid (SA) is used for more than thousands of years in the medical and cosmetology industry. It is a beta hydroxy acid that belongs to a class of phytochemicals known as salicylates, used to treat a wide range of health conditions. It acts as an anti-infective agent, antifungal agent, enzymes inhibitor, and anti-inflammatory and keratolytic agent that help different skin conditions. 1, 2, 4
Topical application of Salicylic acid acts as an exfoliant or peeling agent used to unclog the skin pores, remove debris and bacteria, and improve acne symptoms, pimples, verrucous, skin blemishes, psoriasis, warts, corns, dandruff, keratosis pilaris, calluses, and ringworm. Naturally, willow bark, Sweet birch, and Wintergreen leaves contain a high concentration of salicylic acid and can be extracted for different medicinal uses. 1, 2
The oil-soluble nature of salicylic acid (beta hydroxy acid) makes it highly penetrable into the skin pores for optimal activity. Because studies showed that oil-soluble ingredients like salicylic acid penetrate deeper into the layers of skin compared to water-soluble ingredients. So, Salicylic acid’s oil-soluble nature increases its miscibility with the epidermal lipids and sebaceous gland lipids in the skin layers. That protects the skin against dermatological problems and improves skin complexion, tone, and texture. 1, 4, 5
Uses of Topical SA
Medical research studies reported the following skin benefits of topical salicylic acid.
· In the case of psoriasis, it eases the symptoms and sheds psoriatic scales by providing a soothing and smoothing effect. 1, 4, 17, 20, 21, 22, 23, 24
· SA is also used over the counter remedy for dandruff. It moisturizes the scalp, removes flakes, clears out the dead cells, and maintains an optimal level of scalp motorization. 1, 4, 17, 20, 21, 22, 23, 24
· Moreover, SA helps skin tone and texture via dissolving the glue that holds skin cells and increases skin surface firmness. That improves conditions like wrinkles and pimples, plus glow skin appearance and fade away dark spots. 1, 4, 17, 20, 21, 22, 23, 24
· SA improves redness and itching, soothes inflamed skin, and relieves skin irritation. Thus, it makes it an ideal solution for an individual having seborrheic dermatitis or sensitive skin. 1, 4, 17, 20, 21, 22, 23, 24
· Furthermore, SA acts as an analgesic and skin protectant against poison ivy, ultraviolet radiations, oak, sumac, and topical antifungal products. 4, 17, 20, 21, 22, 23, 24
How Salicylic acid Works
Salicylic acid helps different skin conditions and improves the overall texture and appearance of the skin. Medical studies reported the following actions of topical formulations of Salicylic acid for skin benefits.
- Anti-inflammatory activity: Salicylic acid shows anti-inflammatory action that helps irritation, swelling, and redness of different skin conditions. It inhibits pro-inflammatory mediators’ production, speeds up healing, and improves different types of breakouts or pimples. 1, 2, 3
Exfoliates Skin Debris: Salicylic acid is a known keratolytic agent that removes dead skin cells from the top layers and improves cellular turnover. The exfoliating effect of salicylic acid enhances skin texture and lessens skin dullness. 1, 2, 12, 13
- Helps Clogged Pores: Salicylic acid penetrates well into the deeper layers of skin where it loosens and removes the debris, including toxins, and hazardous agents. It softens and helps eliminate the clogged pores content and reduces the risk of acne, pimples, blackheads, and whiteheads. 15, 16
- Balance Sebum oil Content: Salicylic acid helps the production and content of sebum oil beneath the skin’s surface. It decreases the secretion of sebum and clears out the excess of sebum accumulated in the skin layers and reduces oiliness. This effect not only reduces the risk of many skin conditions but also improves the appearance of the skin. 1, 12, 13
- Target Whiteheads and Blackheads: In the case of whiteheads and blackheads’ skin conditions, it can also directly targets both these conditions and suppress their growth towards the skin surface. 14, 15
Medical research studies about Topical Salicylic acid
Different medical research studies worked on the efficacy and safety of topical salicylic acid and reported the following results:
A 50% ointment paste of SA showed excellent results in the treatment of actinically damaged skin, lentigines, and pigmented keratosis on different parts of the body, including the forearms and hands. 1, 11 Also, it helps and supports other therapeutic remedies in the treatment of comedonal acne, post-acne erythema, and hyperpigmentation due to its high lipophilic nature.1, 9
Furthermore, SA showed good results during photoaging and acne treatment in patients with Fitzpatrick skin type I, II, III, V, and VI. Also, helps mild to moderate photodamage and improve roughness, pigmented lesions, and fine lines in women. 6, 7
A study on patients with the darker racial-ethnic group using 20% -30% SA reported improvements in the symptoms of acne vulgaris, melasma, and hyperpigmentation. Moreover, SA showed an antifungal, antibacterial, and anesthetic effect that relieve symptoms of certain skin conditions. 1, 8
Dosage forms and Concentration of Salicylic acid formulations
Pharmaceutical studies reported different topical dosage forms or SA products, including lotion, drops/solution, gel, sunscreens, shampoos, creams, and ointments intended for different skin conditions. Plus, studies showed that a SA concentration of 0.5% to 2% is effective and free from side effects in treating different skin conditions. While, SA concentration of 3% to 6% is useful for treating dandruff, psoriasis, ichthyosis, and seborrheic dermatitis. 1, 21
How to apply topical formulation of Salicylic acid
All Salicylic acid topical formulations are intended for external use only. Take a sufficient amount of topical formulation, gently apply it over the affected skin area for a specified period, or follow the label directions. Don’t swallow or apply it on wounds, infections, and irritated skin.15
Usually, topical SA formulation does not interact with other drugs used for systemic diseases. However, studies reported the following drugs that might interact with topical Salicylic acid formulations. 17
Normally, the topical Salicylic acid works well on all skin types, but it is not intended for the treatment of skin wounds, warts with hairs, genital warts, oral warts, birthmarks and moles, warts on the face and in the nose. 4, 18, 19
Moreover, it is advised not to use SA in the following conditions: 1
· Active Dermatitis
· Contact Allergy to Salicylates
· Active Infection
· Acute Viral infection
Topical SA is safe and does not cause any side effects. However, some studies reported the following side effects on the application site. 4, 17, 18, 19, 20,
· Skin Dryness
· Skin tingling or stinging
· Peeling skin
· Temporary hair damage
May also causes dizziness, mental confusion, headache, ringing in the ears, and hyperventilation at toxic doses.
It is advised to use the following guidelines for topical application of SA. 17, 18, 19, 20
· Try not to touch or avoid contact with eyes, nose, lips, mouth, and other sensitive areas.
· In the case of pregnancy and breastfeeding, consult your doctor.
· Don’t exceed the recommended dose.
· Avoid application at large areas of the body, for a longer period, and under air-tight dressings.
· SA topical formulations are not intended for children under two year’s age.
· In case of any skin hypersensitivity reactions, allergy, or signs of adverse events, immediately stop its use and contact your doctor.
· Keep it away from children, store it at room temperature, don’t freeze it, and avoid sunlight exposure.
· Prolong use over a large area may cause salicylism.
List of References:
1. Arif T. (2015). Salicylic acid as a peeling agent: a comprehensive review. Clinical, cosmetic and investigational dermatology, 8, 455–461. https://doi.org/10.2147/CCID.S84765
3. Zheng, Y., Wan, M., Chen, H., Ye, C., Zhao, Y., Yi, J., Xia, Y., & Lai, W. (2013). Clinical evidence on the efficacy and safety of an antioxidant optimized 1.5% salicylic acid (SA) cream in the treatment of facial acne: an open, baseline-controlled clinical study. Skin research and technology: official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI), 19(2), 125–130. https://doi.org/10.1111/srt.12022
6. Kligman, D., & Kligman, A. M. (1998). Salicylic acid peels for the treatment of photoaging. Dermatologic surgery: official publication for American Society for Dermatologic Surgery [et al.], 24(3), 325–328. https://doi.org/10.1111/j.1524-4725.1998.tb04162.x
7. Bourelly PE, Lotsikas-Baggili AJ. Chemexfoliation and superficial skin resurfacing. In: Burgess CM, editor. Cosmetic Dermatology. 1st ed. Heidelberg, Germany: Springer-Verlag; 2005.
8. Grimes PE. Salicylic acid. In: Tosti A, Grimes PE, Padova MP, editors. Color Atlas of Chemical Peels. 2nd ed. New York, NY, USA: Springer-Verlag; 2006
9. Monheit GD, Chastian MA. Chemical and mechanical skin resurfacing. In: Bolognia JL, Jorizzo JL, Rapini RP, editors. Dermatology. Philadelphia, PA, USA: Mosby; 2003.
10. Madan, R. K., & Levitt, J. (2014). A review of toxicity from topical salicylic acid preparations. Journal of the American Academy of Dermatology, 70(4), 788–792. https://doi.org/10.1016/j.jaad.2013.12.005
11. Swinehart J. M. (1992). Salicylic acid ointment peeling of the hands and forearms. Effective nonsurgical removal of pigmented lesions and actinic damage. The Journal of dermatologic surgery and oncology, 18(6), 495–498. https://doi.org/10.1111/j.1524-4725.1992.tb03311.x
12. Marczyk, B., Mucha, P., Budzisz, E., & Rotsztejn, H. (2014). Comparative study of the effect of 50% pyruvic and 30% salicylic peels on the skin lipid film in patients with acne vulgaris. Journal of cosmetic dermatology, 13(1), 15–21. https://doi.org/10.1111/jocd.12050
13. Roberts, D. L., Marshall, R., & Marks, R. (1980). Detection of the action of salicylic acid on the normal stratum corneum. The British journal of dermatology, 103(2), 191–196. https://doi.org/10.1111/j.1365-2133.1980.tb06590.x
16. Rodan, K., Fields, K., Majewski, G., & Falla, T. (2016). Skincare Bootcamp: The Evolving Role of Skincare. Plastic and reconstructive surgery. Global open, 4(12 Suppl Anatomy and Safety in Cosmetic Medicine: Cosmetic Bootcamp), e1152. https://doi.org/10.1097/GOX.0000000000001152
23. Vanessa Ngan, 2015, “Salicylic acid”, https://dermnetnz.org/topics/salicylic-acid/