Rainbow Nails' Blog

Recently, every move of Nvidia CEO Jensen Huang has been in the spotlight, but who would have thought his “thumb” would also become a focal point! A netizen captured a close-up photo of his grayish-black thumbnail and even posted a warning: “If you meet Jensen Huang, don’t shake his hand, beware of catching a fungal nail infection.” This post instantly attracted over a million views.

But wait, does a black nail definitely mean a fungal infection? Is it really contagious through a handshake? Today, through the professional analysis of authoritative dermatologists and ENT doctors, we will teach you how to debunk the myths of nail discoloration and easily distinguish between a “fungal nail” and a “trauma bruise”!

Debunking the Myth: Is shaking hands with someone with “black nails” contagious?
First, the question everyone cares about most: A normal handshake will not transmit a fungal nail infection!
Specialist doctors point out that although a fungal nail is a fungal infection, it usually occurs in people with weaker immune systems. Unless your own nail happens to have a defect or wound, a simple polite handshake is very safe. The excessive panic among netizens is really unnecessary!

Practical Guide: How to distinguish between a “fungal nail” and a “bruise”?
The most common cause of nails turning black or gray is actually trauma, followed by infection. You can make an initial self-assessment through the following key points:

Trauma Bruise (Subungual Hematoma)

• Cause: Usually has a clear history of injury, such as being caught in a door, hit by a heavy object, or getting a “jammed finger” during sports.
• Appearance: The color is mostly purplish-black or grayish-black with a hint of bruising.
• Accompanying symptoms: In the early stages of injury (first 2 to 3 days), there will be noticeable swelling and severe pain.
• Affected area: Usually, only the “injured” nail will change color.
• Recovery time: Because the blood circulation under the nail is poor, the bruise fades very slowly. It usually takes nearly a month or even longer, and will slowly be pushed out as the new nail grows.

Fungal Nail (Onychomycosis)

• Cause: Fungal infection, often occurring in people who frequently touch water, have poor immunity, or have hot, sweaty feet (more common on toes than fingers).
• Appearance: The nail not only changes color (may turn yellow, gray, or black) but is also accompanied by thickening, brittleness, crumbling, or even separation from the nail bed.
• Accompanying symptoms: Usually painless in the early stages.
• Affected area: Fungi are contagious and usually affect several adjacent nails, but rarely affect “all ten fingers.”

How do specialist doctors view Jensen Huang’s nails?
Authoritative dermatologist Dr. Chou Tsu-man analyzed that not only is Jensen Huang’s thumb discolored, but several other fingers also have dullness, and the nail folds show signs of damage from frequent contact with water. This situation of “multiple fingers changing color at the same time” is more likely caused by pigmentation from taking specific medications (such as antibiotics, immunosuppressants, etc.), or damage to the nail folds due to over-cleaning/frequent contact with water, which affects nail growth, rather than a fungal infection.

Bonus: Could a black nail be skin cancer?
Many people worry that a dark shadow on their nail might be a terrifying “malignant melanoma.” Doctors remind us that if your nail shows the following 5 major warning signs, be sure to seek medical attention as soon as possible:

1. The color intensity, line thickness, or spacing of the black streaks are uneven.
2. The pigment extends and bleeds into the skin in front of the nail.
3. The streak presents a triangular shape that is “narrow at the front and wide at the back.”
4. The black streak covers more than 2/3 of the nail surface.
5. The black streaks are suddenly discovered after the age of 50.

(Note: Jensen Huang’s black nails are mostly on the distal 2/3, with no pigmentation on the proximal end, so doctors judge the probability of a malignant tumor to be extremely low.)

Accidentally pinched your finger? First aid for a bruised nail
If you really accidentally pinch your hand, causing a subungual hematoma, please remember the following first aid steps:

• Acute phase icing: Within a few hours after the injury, apply an ice pack (ice water in a plastic bag) wrapped in a towel (apply for 10 minutes, rest for 30 minutes) to reduce swelling and pain.
• Seek medical attention for severe swelling and pain: If the pain is unbearable, doctors can make a small hole in the nail for “drainage and decompression,” which can instantly and significantly relieve the pain. If bone damage is suspected, an X-ray is also needed for confirmation!

Conclusion
Nails are like a “small window” to your body’s health. Color changes may indicate trauma, nutritional deficiencies (such as lack of calcium or protein), or medication effects. Next time you see someone with a different nail color, don’t rush to fear being infected. With a little more medical common sense, you can avoid unnecessary panic! If you have doubts about your own nail condition, the safest approach is always to seek a professional diagnosis directly from a dermatologist!