Acute Kidney Injury and Hair-Straightening Products: A Case Series.

RATIONALE & OBJECTIVE: Keratin-based hair-straightening treatment is a popular hair-styling method. The majority of keratin-based hair-straightening products in Israel contain glycolic acid derivatives, which are considered safe when used topically. Systemic absorption of these products is possible, and anecdotal reports have described kidney toxicity associated with their use. We report a series of cases of severe acute kidney injury (AKI) following use of hair-straightening treatment in Israel during the past several years. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: We retrospectively identified 26 patients from 14 medical centers in Israel who experienced severe AKI and reported prior treatment with hair-straightening products in 2019-2022. FINDINGS: The 26 patients described had a median age of 28.5 (range, 14-58) years and experienced severe AKI following a hair-straightening procedure. The most common symptoms at presentation were nausea, vomiting, and abdominal pain. Scalp rash was noted in 10 (38%) patients. Two patients experienced a recurrent episode of AKI following a repeat hair-straightening treatment. Seven patients underwent kidney biopsies, which demonstrated intratubular calcium oxalate deposition in 6 and microcalcification in tubular cells in 1. In all biopsies, signs of acute tubular injury were present, and an interstitial infiltrate was noted in 4 cases. Three patients required temporary dialysis. LIMITATIONS: Retrospective uncontrolled study, small number of kidney biopsies. CONCLUSIONS: This series describes cases of AKI with prior exposure to hair-straightening treatments. Acute oxalate nephropathy was the dominant finding on kidney biopsies, which may be related to absorption of glycolic acid derivatives and their metabolism to oxalate. This case series suggests a potential underrecognized cause of AKI in the young healthy population. Further studies are needed to confirm this association and to assess the extent of this phenomenon as well as its pathogenesis.

Combined use of CRP with neutrophil-to-lymphocyte ratio in differentiating between infectious and noninfectious inflammation in hemodialysis patients.

We tested whether CRP combined with the neutrophil-to-lymphocyte ratio (NLR) optimizes the prediction of infectious inflammation in hemodialysis patients. We conducted a retrospective study of 774 (mean age 71.1 ± 12.8 years, 35% women) hemodialysis patients from our institution, hospitalized between 2007 and 2021 for various reasons, with CRP levels available at admission. Infection was defined according to the International Sepsis Definition Conference criteria. An algorithm for the optimal CRP and NLR cutoff points for predicting infection was developed based on a decision tree analysis in the training cohort (n = 620) and then tested in the validation cohort (n = 154). A CRP level above 40 mg/L (obtained as the cutoff point in predicting infections in the training group, using ROC curve analysis) predicted an infection diagnosis with a sensitivity of 75% and a specificity of 76% with an odds ratio (OR) of 9.37 (95% CI: 5.36-16.39), according to a multivariate logistic regression analysis. Whereas, CRP levels above 23 mg/L together with an NLR above 9.7 predicted an infection diagnosis with a sensitivity of 69% and a specificity of 84% with an OR of 25.59 (95% CI: 9.73-67.31). All these results were reproduced in the validation set. Combined use of CRP with NLR may lower the CRP cutoff point in distinguishing between infectious and noninfectious inflammation in hemodialysis patients.