Acute kidney injury (AKI) from toxin exposure is seen with systemic medications, including analgesics, certain antibiotics, and anti-neoplastic medications (1). However, the association of AKI with topical toxin exposure is not commonly recognized.
In a recent publication by Bnaya et al. (2) in the American Journal of Kidney Diseases, the authors reported a case series of 26 patients who developed AKI following exposure to hair-straightening products in Israel, suggesting an under-recognized cause of AKI.
Keratin-based hair straightening is a popular method used to style hair. Previous hair products were formaldehyde-based, but formaldehyde was found to be carcinogenic (3). Thus, straightening products in Israel have largely been replaced by glycolic acid derivatives because they were considered to be safe when used topically. However, as reported in this case series, the use of hair-straightening products that contain glycolic acid derivatives may not be as safe as it appears.
The authors reported that 26 patients developed severe AKI following the hair-straightening procedure, with three of them requiring temporary dialysis. Two of the patients had recurrent AKI episodes each time following hair-straightening procedures. Seven patients underwent a kidney biopsy, in which five of them showed oxalate nephropathy, one showed a few calcium oxalate crystals, and another showed micro-calcification in the tubular epithelium. Given that glycolic acid is within the metabolic pathway of oxalate formation (Figure 1), the authors have attributed the AKI to glycolic acid.
AKI following hair-straightening treatment: suggested mechanism
Citation: Kidney News 15, 5
AGT, alanine:glyoxylate aminotransferase; GO, glycolate oxidase; HOGA, 4-hydroxy-2-oxoglutarate aldolase; LDH5, lactate dehydrogenase 5. The figure is adapted from Bnaya et al. (2).AKI following hair-straightening treatment: suggested mechanism
Citation: Kidney News 15, 5
AGT, alanine:glyoxylate aminotransferase; GO, glycolate oxidase; HOGA, 4-hydroxy-2-oxoglutarate aldolase; LDH5, lactate dehydrogenase 5. The figure is adapted from Bnaya et al. (2).AKI following hair-straightening treatment: suggested mechanism
Citation: Kidney News 15, 5
AGT, alanine:glyoxylate aminotransferase; GO, glycolate oxidase; HOGA, 4-hydroxy-2-oxoglutarate aldolase; LDH5, lactate dehydrogenase 5. The figure is adapted from Bnaya et al. (2).Systemic absorption of glycolic acid through the skin is not well-documented. In this case series, only two people had serum glycolic acid and formic acid levels measured. The levels were negative for both, but one test was only performed 1 week after the hair-straightening procedure. Other studies have suggested that glycolic acid can be absorbed through the skin, particularly when the product has a low pH and high concentration of glycolic acid and the exposure time on the skin is prolonged (4, 5).
This case series suggests that a glycolic acid-based hair-straightening product is associated with the development of AKI. Although glycolic acid-based topical products have been considered safe, it is possible that systemic absorption may occur at high concentrations. Thus, caution must be taken when considering the safety of hair products. Future studies are needed to understand the extent of the problem.
References
- 1. ↑
Pierson-Marchandise M, et al. The drugs that mostly frequently induce acute kidney injury: A case–noncase study of a pharmacovigilance database. Br J Clin Pharmacol 2017; 83:1341–1349. doi: 10.1111/bcp.13216
- 2. ↑
Bnaya A, et al. Acute kidney injury and hair straightening products: A case series. Am J Kidney Dis (published online ahead of print January 4, 2023). doi: 10.1053/j.ajkd.2022.11.016; https://www.ajkd.org/article/S0272-6386(23)00006-9/fulltext
- 3. ↑
National Cancer Institute. Formaldehyde and cancer risk. Updated 2011. Accessed February 6, 2023. https://www.cancer.gov/about-cancer/causes-prevention/risk/substances/formaldehyde/formaldehyde-fact-sheet#:~:text=The%20International%20Agency%20for%20Research,Report%20on%20Carcinogens%20(3)
- 4. ↑
Jiang M, Qureshi SA. Assessment of in vitro percutaneous absorption of glycolic acid through human skin sections using a flow-through diffusion cell system. J Dermatol Sci 1998; 18:181–188. doi: 10.1016/s0923-1811(98)00039-5
- 5. ↑
Copoví A, et al. Enhancing effect of alpha-hydroxyacids on “in vitro” permeation across the human skin of compounds with different lipophilicity. Int J Pharm 2006; 314:31–36. doi: 10.1016/j.ijpharm.2006.01.033
