In a new Journal of Medical Case Reports article, AlKhalaf and colleagues describe a previously healthy 39-year-old Saudi woman who developed vomiting, diarrhea, back pain, and stage 3 acute kidney injury three days after undergoing chemical hair straightening. Her serum creatinine increased from 86.9 to 624.2 µmol/L. Urine culture was negative, autoimmune testing was unrevealing, and renal ultrasonography showed no structural abnormality.
Kidney biopsy provided the decisive evidence. Histopathology demonstrated interstitial edema, eosinophilic inflammation, focal white-cell casts, acute tubular injury, and scattered oxalate crystals, supporting acute interstitial nephritis with oxalate-associated nephropathy. The biopsy images illustrate both the inflammatory tubular injury and crystalline deposits under routine and polarized microscopy.
The patient received intravenous methylprednisolone followed by oral prednisolone and supportive care. Renal function improved progressively, with creatinine ultimately returning to 84.2 µmol/L. Renal replacement therapy was not required.
The proposed mechanism involves glyoxylic acid or related glycolic compounds that can be absorbed through the scalp and metabolized to oxalate. Calcium oxalate deposition may then produce tubular injury and crystalline nephropathy. Importantly, this risk may not be limited to products marketed as containing formaldehyde; similar events have been reported after use of products labelled “formaldehyde-free.”
The report has an important limitation: the exact hair-straightening product and its chemical composition could not be identified. The temporal association and biopsy findings therefore support, but do not by themselves prove, causation. Nevertheless, the case strengthens the clinical signal linking some hair-straightening formulations with potentially severe but reversible kidney injury.
Clinical Take-Home Message
In patients presenting with otherwise unexplained acute kidney injury, particularly when accompanied by gastrointestinal symptoms or back pain, clinicians should ask specifically about recent cosmetic hair treatments. Early recognition, discontinuation of exposure, appropriate nephrological evaluation, and kidney biopsy when indicated may permit timely treatment and complete renal recovery.
Reference
AlKhalaf M, AlKhudair A, El Tawil E. Acute kidney injury following the use of chemical hair straightener: a case report. Journal of Medical Case Reports. 2026. doi:10.1186/s13256-026-06315-1.
Journal of Medical Case Reports is the world’s first international, PubMed-listed, medical journal devoted to publishing case reports from all medical disciplines and will consider any original case report that expands the field of general medical knowledge, and original research relating to case reports. The journal is open access, and strongly endorses the CARE guidelines for case reports, requiring authors to submit populated CARE checklists with submissions to improve transparency in reporting.