This article details a case report of patients developing rare, life-threatening Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) after taking Metronidazole and Mebendazole—even when taken six weeks apart.
Introduction
Imagine taking a common medication only to develop a life-threatening skin reaction. This was the terrifying reality for several Filipino workers in Taiwan in 1996.
A study published in the American Journal of Public Health in March 2003 investigated an outbreak of Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN)—two severe and potentially fatal skin conditions—among Filipino laborers. The study found a strong link between these conditions and the combined use of the antiparasitic drugs metronidazole and mebendazole.
What Are SJS and TEN?
Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are severe skin reactions that occur in response to infections, medications, or other triggers.
Both conditions involve painful blistering and peeling of the skin, but they vary in severity:
- SJS affects less than 10% of the body’s surface.
- TEN is more severe, affecting more than 30% of the skin.
In both cases, the immune system mistakenly attacks the skin and mucous membranes, leading to painful sores, fever, and potentially fatal complications.
The prognosis is poor, with a case fatality rate of 30% to 40%. Milder forms are known as SJS or SJS/TEN overlap.
Background: The Filipino Worker Health Screening Policy
Since 1989, Taiwan has allowed laborers from Southeast Asian countries to work in factories, and by 1993, a mandatory health screening program was in place.
This required workers to undergo medical exams within seven days of arrival and every six months thereafter.
A critical part of this screening was a stool test for intestinal parasites.
To avoid failing the test, many laborers took antiparasite or anthelminthic drugs, such as metronidazole and mebendazole, before their scheduled exams. Unfortunately, this seemingly harmless act had devastating consequences.
The 1996 Outbreak: What Happened?
In August 1996, six female Filipino workers at an electronics factory in Taiwan were hospitalized with severe skin rashes, fever, and liver issues. One worker tragically died.
Three months later, in November 1996, four more Filipino women from the same factory were hospitalized with identical symptoms. Their shared living conditions and the clustering of cases raised alarms, prompting an investigation by Taiwan’s Department of Health.
Key Findings of the Study
To understand what triggered these severe reactions, 46 patients diagnosed with SJS/TEN were compared with 92 healthy control individuals. The researchers found:
- Workers who had taken both metronidazole and mebendazole within the previous six weeks were 9.5 times more likely to develop SJS/TEN compared to those who had not.
- The risk increased the more metronidazole was taken, showing a dose-dependent effect.
- No evidence linked the outbreak to viral infections, ruling out other possible causes.
Why Did This Happen?
Metronidazole and mebendazole are commonly used to treat parasitic infections, but when taken together, they appear to have triggered an extreme immune response in some individuals.
Implications and Lessons Learned
This outbreak underscores the hidden dangers of self-medicating without proper medical supervision. The findings led to important changes, including:
- Stronger drug safety regulations to prevent inappropriate use of metronidazole and mebendazole together.
- Greater awareness of severe drug reactions among healthcare providers.
- Improved monitoring of foreign laborers’ health to prevent future outbreaks.
What You Can Do to Stay Safe
- Never take medications unnecessarily, especially without a doctor’s guidance.
- Report unusual symptoms (skin rash, fever, mouth sores) immediately when taking a new medication.
- If you have a history of drug allergies, always inform healthcare professionals before starting any treatment.
Conclusion
The 1996 SJS/TEN outbreak in Taiwan was a tragic but eye-opening event that revealed the serious risks of combining certain medications.
While metronidazole and mebendazole are generally safe when used separately, their combined use led to devastating consequences.
This case highlights the importance of drug safety, medical supervision, and awareness of potential side effects—a crucial lesson for everyone today.
Don’tGet Sick!
Chen KT, Twu SJ, Chang HJ, Lin RS. Outbreak of Stevens-Johnson syndrome/toxic epidermal necrolysis associated with mebendazole and metronidazole use among Filipino laborers in Taiwan. Am J Public Health. 2003 Mar;93(3):489-92. doi: 10.2105/ajph.93.3.489. PMID: 12604501; PMCID: PMC1447769.
Image credits:
- Tongue Stevens-Johnson syndrome. (2024, November 10). In Wikipedia. https://en.wikipedia.org/wiki/Stevens%E2%80%93Johnson_syndrome
- Lips Stevens-Johnson syndrome. (2024, November 10). In Wikipedia. https://en.wikipedia.org/wiki/Stevens%E2%80%93Johnson_syndrome
- Conjunctiva By Jonathan Trobe, M.D., University of Michigan Kellogg Eye Center – http://www.kellogg.umich.edu/theeyeshaveit/acquired/conjunctivitis.html, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=8406623
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