Medicine:Medical uses of salicylic acid

From HandWiki
Short description: Overview of a common topical medication
Salicylic acid
Salicylic acid pads.jpg
Cotton pads soaked in salicylic acid for medical use
Clinical data
Trade namesVarious trade names
AHFS/Drugs.comMultum Consumer Information
Routes of
administration
topical
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailabilitylow
Identifiers
CAS Number
PubChem CID
DrugBank
ChemSpider
UNII
Chemical and physical data
FormulaC7H6O3
Molar mass138.122 g·mol−1
3D model (JSmol)

Salicylic acid is used as a medicine to help remove the outer layer of the skin.[1] As such it is used to treat warts, skin tags, calluses, psoriasis, dandruff, acne, ringworm, and ichthyosis.[1][2] For conditions other than warts, it is often used together with other medications.[2] It is applied to the area affected.[1]

Side effects include skin irritation, and salicylate poisoning.[2] Salicylate poisoning tends to only occur when applied to a large area and in children.[2] Use is thus not recommended in children less than two years old.[2] It comes in a number of different strengths.[3]

It is on the World Health Organization's List of Essential Medicines.[4][5] It is also available mixed with coal tar, zinc oxide, or benzoic acid.[3]

Medical uses

Salicylic acid as a medication is used to help remove the outer layer of the skin.[1] As such it is used to treat warts, calluses, psoriasis, dandruff, acne, ringworm, and ichthyosis.[1][2]

Because of its effect on skin cells, salicylic acid is used in some shampoos to treat dandruff.

In modern medicine, salicylic acid and its derivatives are constituents of some "skin-reddening" products.

Side effects

Concentrated solutions of salicylic acid may cause hyperpigmentation on people with darker skin types (Fitzpatrick phototypes IV, V, VI), without a broad spectrum sunblock.[6][7] Due to sun sensitivity, sun protection is recommended when using salicylic acid on sun-exposed skin.[8]

Pregnancy

No studies examine topical salicylic acid in pregnancy. The risks of aspirin late in pregnancy are probably not relevant for a topical exposure to salicylic acid, even late in the pregnancy, because of its low systemic levels. Topical salicylic acid is common in many over-the-counter dermatological agents and the lack of adverse reports suggests a low risk.[9]

Overdose

Side effects include skin irritation, and salicylate poisoning.[2] Salicylate poisoning tends to only occur when applied to a large area and in children.[2] Use is thus not recommended in children less than two years old.[2] It comes in a number of different strengths.[3]

Salicylic acid overdose can lead metabolic acidosis with compensatory respiratory alkalosis. In people presenting with an acute overdose, a 16% morbidity rate and a 1% mortality rate are observed.[10]

Mechanism of action

Salicylic acid works as a keratolytic, comedolytic and bacteriostatic agent, causing the cells of the epidermis to shed more readily, opening clogged pores and neutralizing bacteria within, preventing pores from clogging up again and allowing room for new cell growth.[11][12]

History

Dioscorides, in the first century AD, described the use of an extract of what might have been willow bark (a plant he called Itea),[13] 'being burnt to ashes, and steeped in vinegar,'[14] for taking away 'corns and other like risings in the feet and toes.' The active ingredient in this mixture could have been salicylic acid, but it is a modern myth that willow was ever used to ease aches and pains or reduce fevers.[11][15]

References

  1. 1.0 1.1 1.2 1.3 1.4 "Salicylic acid topical medical facts". Drugs.com. https://www.drugs.com/mtm/salicylic-acid-topical.html. 
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 WHO Model Formulary 2008. World Health Organization. 2009. p. 310. ISBN 9789241547659. 
  3. 3.0 3.1 3.2 British national formulary : BNF 69 (69 ed.). British Medical Association. 2015. pp. 814–815, 825, 833. ISBN 9780857111562. 
  4. World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. 2019. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO. 
  5. World Health Organization model list of essential medicines: 22nd list (2021). Geneva: World Health Organization. 2021. WHO/MHP/HPS/EML/2021.02. 
  6. "The safety and efficacy of salicylic acid chemical peels in darker racial-ethnic groups". Dermatologic Surgery 25 (1): 18–22. January 1999. doi:10.1046/j.1524-4725.1999.08145.x. PMID 9935087. 
  7. "Chemical peeling in ethnic/dark skin". Dermatologic Therapy 17 (2): 196–205. 2004. doi:10.1111/j.1396-0296.2004.04020.x. PMID 15113287. 
  8. "Beta Hydroxy Acids in Cosmetics". Center for Food Safety and Applied Nutrition, Office of Cosmetics and Colors Fact Sheet. U.S. Food and Drug Administration. 7 March 2000. http://www.cfsan.fda.gov/~dms/cos-bha.html. 
  9. "Acne and Pregnancy". Illinois Teratogen Information Service. 2000. http://www.fetal-exposure.org/ACNE.html. 
  10. Salicylate Toxicity at eMedicine
  11. 11.0 11.1 "A review of toxicity from topical salicylic acid preparations". Journal of the American Academy of Dermatology 70 (4): 788–792. April 2014. doi:10.1016/j.jaad.2013.12.005. PMID 24472429. 
  12. "The Bacteriostatic Action of Benzoic and Salicylic Acids." (in en). Physiologia Plantarum 13 (4): 800–811. 1960-10-01. doi:10.1111/j.1399-3054.1960.tb08103.x. ISSN 1399-3054. 
  13. De Materia Medica. Ibidis. 2000. ISBN 0-620-23435-0. https://ia802907.us.archive.org/16/items/de-materia-medica/scribd-download.com_dioscorides-de-materia-medica.pdf. Retrieved 12 January 2022. 
  14. "Of the Willow Tree". Herball, or Generall Historie of Plantes. https://www.exclassics.com/herbal/herbalv50587.htm. Retrieved 12 January 2022. 
  15. "The Mythology of Aspirin". Skeptoid Media, Inc.. 22 May 2014. https://skeptoid.com/blog/2014/05/22/the-mythology-of-asprin/.