Ask Onix
Earwax: A new frontier in disease detection
Scientists are turning to earwax-long overlooked as a bodily secretion-to uncover early signs of cancer, diabetes, heart disease, and neurodegenerative disorders. Research suggests the sticky substance may offer a simpler, non-invasive way to diagnose conditions that currently require complex tests.
What earwax reveals about health
Cerumen, the medical term for earwax, is produced by glands in the outer ear canal and contains a mix of secretions, dead skin, and debris. While its primary role is to protect the ear by trapping bacteria and debris, its chemical composition also reflects metabolic processes in the body.
Studies have linked specific earwax traits to health conditions. For instance, wet earwax-common in people of European or African descent-has been associated with a higher risk of breast cancer in some studies, though findings remain debated. Meanwhile, dry earwax, prevalent in East Asian populations, is tied to a gene that also reduces body odor.
Breakthroughs in disease detection
Researchers have identified biomarkers in earwax for several conditions. A rare genetic disorder called maple syrup urine disease, which affects amino acid metabolism, leaves a distinct sweet odor in earwax, detectable without genetic testing. Similarly, COVID-19 and diabetes have been traced in earwax samples.
One of the most promising discoveries involves Ménière's disease, an inner-ear disorder causing vertigo and hearing loss. Scientists at Louisiana State University found that patients with the condition have lower levels of three fatty acids in their earwax, offering the first potential biomarker for early diagnosis.
"Our interest in earwax is directed at illnesses that are difficult to diagnose using typical biological fluids like blood or urine," said Rabi Ann Musah, an environmental chemist leading the research.
The science behind earwax's diagnostic potential
Earwax's lipid-rich composition makes it a unique repository of metabolic byproducts. Unlike blood or urine, which are water-based, earwax captures fat-soluble compounds that may signal disease earlier. Nelson Roberto Antoniosi Filho, a chemist at Brazil's Federal University of Goiás, likens it to a "long-term snapshot" of metabolic changes.
His team developed the "cerumenogram," a diagnostic tool that analyzes volatile organic compounds (VOCs) in earwax. In a 2019 study, the method accurately identified cancer (lymphoma, carcinoma, or leukemia) in patients by detecting 27 specific molecules. While it couldn't distinguish between cancer types, it detected pre-cancerous metabolic changes, potentially improving early intervention.
Future applications and challenges
A Brazilian hospital has already adopted the cerumenogram to monitor cancer treatment. Researchers are now exploring its use for Parkinson's and Alzheimer's, though these studies are in early stages. Musah's team is developing an over-the-counter test kit for Ménière's disease, similar to COVID-19 rapid tests.
However, experts caution that more research is needed. Perdita Barran, a chemist at the University of Manchester, noted that earwax's lipid-rich nature could reveal metabolic shifts missed in blood tests, but standardized profiles for healthy earwax are still lacking.
"Earwax is a wonderful matrix because it's lipid-rich, and many diseases stem from lipid metabolism dysregulation," Musah said.
What's next?
Scientists envision earwax analysis becoming a routine clinical tool, offering a painless, cost-effective way to screen for multiple diseases simultaneously. If validated, it could transform diagnostics, particularly for conditions that currently require invasive or time-consuming tests.
