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'Swamp Crotch' Sparks TSA Drama at Airport Scanners

By Jessie Stone • Jul 10, 2025

It's not just piercings or hidden items that could get you pulled aside by airport security. Some travelers are finding themselves flagged for something far less suspicious — and a lot sweatier.

When Sweat Becomes Suspicious

A woman flying for the first time in 15 years recently found herself stopped twice at airport security, both times for the same reason — her groin area triggered an alert during TSA's body scan.

No metal, no devices, no hidden objects. Just sweat.

The woman, who described herself as "midsized" and wearing normal bike shorts and underwear, shared her baffling experience on Reddit, sparking a surprising wave of similar stories from fellow fliers, according to VICE.

The common denominator? Excess moisture — also known colloquially as "swamp crotch."

Why It Happens

The TSA uses millimeter wave scanners that don't just detect metal. They pick up anything that interferes with the signal, including moisture. According to TSA expert Shawna Malvini Redden, perspiration is one of the stranger causes of false positives. The scanner's technology reacts to the way waves bounce off water, making sweat a surprising trigger for additional screening.

Medical professionals echo this. Professor Franklin Joseph, head of Dr. Frank's Clinic, explained to The Sun that the groin area contains many sweat glands. In warm weather or tight clothes, it's one of the first places to get damp — especially if you're anxious or rushing through the terminal. This can create visible patches or anomalies on scanner images that flag security concerns.

Beyond Sweat: Other Factors That Trigger Scanners

Sweat isn't the only culprit. Feminine hygiene products, snug underwear, and even body shape have all been reported to set off alarms. TSA states their equipment is designed to screen all body types effectively. Still, fuller-figured passengers or those wearing compression garments sometimes find themselves pulled aside more often.

One traveler noted the situation can be awkward, but TSA agents were professional and courteous during her pat-downs. Still, some fliers expressed confusion or frustration over being repeatedly flagged for what amounts to a very human condition.

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Other Countries Have Opted Out

Interestingly, some countries have backed away from using this technology. France and Germany reportedly scrapped millimeter wave scanners due to the high rate of false positives. But in the U.S., the scanners remain a standard part of the security process.

What You Can Do

If you're worried about getting stopped over sweat, consider packing moisture-wicking underwear, applying anti-chafing powder, or opting for breathable cotton layers. Doctors also recommend staying hydrated and changing out of damp clothes quickly to avoid not just scanner trouble but potential health issues like irritation or infections.

General practitioner Dr. Claire Merrifield also advises washing the groin and underarm areas regularly, especially in hot climates or for people prone to excessive sweating. She recommends using fragrance-free products and changing clothes often when traveling.

The Bottom Line

It may sound ridiculous, but "swamp crotch" really can hold you up at airport security. While the TSA insists its technology is safe and effective, travelers with damp clothing may find themselves the subject of unexpected scrutiny. The solution might not be high-tech — it might just be dry shorts.

References: People With Swamp Crotch Keep Setting Off TSA Alarms | Passenger Flagged by TSA After 'Swamp Crotch' Sets Off Alarm — and It's Happening to Others, Too | 'Swamp Crotch' Is Setting Off Airport Security Scanners as GP Reveals Who's at Risk and How to Avoid the 'Embarrassment'

The Truthfully team was assisted by generative AI technology in creating this content
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