When You Run, What Falls Out Is Not Your Hair but Your Armpit Hair (Armpit Hair Loss)

Have you ever worried that your hair might fall out when you exercise?

But this time, it is not the hair on your head; it is armpit hair.

In fact, a case in which hair became tangled from friction during exercise and eventually led to hair loss has been officially reported in the United States.

Let’s take a look at this unfamiliar but possible skin condition that can happen to anyone: “Scratch.”

Pain During Exercise? A Warning From the Skin We Didn’t Know About

"Ah, why does it hurt so much here?"

When running, sometimes your clothing can be more of a problem than your body.

As you swing your arms repeatedly, the skin under your armpits can sting.

In such cases, it may be “Scratch.”

A Real Case: A Man Whose Armpit Hair Clumped Together During a Marathon

Source - Health Chosun

Recently, medical staff at UC Davis Medical Center in California, USA, reported an interesting case.

A 66-year-old man, Mr. A, felt pain in his left armpit during a half marathon,

and when he checked, he found that his armpit hair had clumped together.

After tearing it off by hand and visiting a hospital, he was diagnosed with “Scratch”

and also experienced temporary hair loss.

This phenomenon occurs when hair becomes tangled due to repeated friction between athletic wear and the skin,

and it can commonly happen during activities such as running.

Scratch Is Not Just a Simple Tangle of Hair

Even if it looks like nothing more than a simple clump of hair, leaving it untreated can lead to secondary conditions such as bacterial infection, contact dermatitis, and pigmentation.

This is because moisture can build up in the injured area where the hair has been pulled out, creating an environment where bacteria can thrive.

Therefore, it is better not to tear out clumped hair by hand, but to carefully cut it off with a hygienic pair of scissors.

Lifestyle Habits to Prevent Scratch

• Hair removal before exercise: It is recommended to remove hair in advance to reduce friction.

• Choose breathable clothing: Sleeveless or loose-fitting clothes are more effective than tight long sleeves.

• Wear functional materials: Athletic wear that reduces skin friction is recommended.

• Keep in mind that many athletes are making hair removal part of their routine not only to improve performance but also to protect their skin.

Nipples Are Not Exempt Either

Not only the armpits, but nipples can also be damaged by friction during exercise.

In particular, when sweat causes clothing and nipples to stick together, continuous friction can lead to bleeding or pain.

Try practicing the following preventive measures.

• Protect nipples with sports tape or disposable bandages

• Use moisturizer to prevent skin dryness

• Change underwear often to maintain cleanliness

If symptoms such as swelling or oozing occur, it is important to seek medical attention immediately.

“Scratch,” a Common Condition That Can Affect All of Us

“Scratch” may still be unfamiliar because it has not been widely reported officially yet.

However, it is a skin condition that anyone can experience during exercises that involve a lot of arm movement, such as marathon running, gym workouts, and hiking.

Skin and hair are not merely cosmetic concerns; they are directly related to health.

Simple care and prevention before and after exercise can reduce discomfort and help protect your health.

It’s time to hairhair, this was Kim Jin-o.

Pilsaengsinmo (必生新毛).

References

A case published in the American medical journal [Cureus] on May 31, 2025

[This post was written directly by a board-certified plastic surgeon for the purpose of providing information in accordance with Article 56, Paragraph 1 of the Medical Service Act. Hair transplant surgery and treatment may have side effects, and careful decisions should be made through consultation with a specialist.]