His Fingernails Were Purple but Didn’t Hurt. What Was This?

“We’ve got to do something about your hands,” the woman said to her 67-year-old husband as she watched his darkened fingertips tapping at the keyboard. The man glanced down from the screen to his hands. She was right; they were worse. He first noticed the change a couple of weeks earlier, just after he fell playing Pickleball, a mash-up of racquetball, tennis and Ping-Pong. He’d leaned in to return a well-placed shot and fallen over, slamming his left hand into the wooden court as he fell onto his right shoulder. He got up, feeling his dignity was injured more than the rest of him, and finished the game. But while showering, he noticed the darkened nails of his slammed left hand. They were the purple shade of a bruise. Strangely, the nails on his right hand were also dark. His fingers didn’t hurt, but the nails had taken on an ominous violet hue.

He’d had a pretty bad fall, his wife agreed when he showed her his darkened nails. Maybe he’d bruised them. Because the nails weren’t tender or painful, the man decided to ignore it. And sure enough, over the next few days, the bruised-​looking color began to fade. But the darkness never completely cleared up. And now it was back, even darker than before.

At a previously scheduled appointment for his annual physical, the man mentioned his discolored nails to his internist. The doctor wasn’t sure what it was, either. He quickly looked up nail melanoma to make sure this wasn’t a cancer. Nope; if this was melanoma, it would be limited to a single nail. The doctor asked if he had any other symptoms. Nothing. “Keep an eye on it,” he said. The patient promised to let him know if anything changed.

And nothing really changed. Sometimes the nails were darker, sometimes lighter. But the color didn’t go away. After a few more weeks, the man called an old friend, Mike Fishbein, a radiologist at Falmouth Hospital on Cape Cod in Massachusetts. “What do you know about purple fingernails?” he asked. Fishbein was an internist before training to become a radiologist, and he was immediately worried. Can you send me a picture? he asked. The picture showed purple nails on both hands. This wasn’t reassuring. The first thing that came to Fishbein’s mind was cyanosis — not getting enough oxygen to the tissues.

Moreover, just a week earlier, a friend’s son had developed painful purple toes. It turned out that was his first symptom of infection with Covid-19. He pummeled his friend with questions: Do you have a fever or a cough? Are you short of breath? Do your fingers hurt? No, said the patient; he had none of those symptoms. He felt fine. It’s just that his fingernails were bruised-looking. Fishbein told him he should get his oxygen level checked. This could be bad. The nearby walk-in clinic was closed, so Fishbein invited his friend over to his place for the test.

When the patient arrived, Fishbein quickly checked his oxygen saturation with a small monitor that he slid over one finger. It was 99 percent — completely normal. The doctor took off his glasses and brought one of the man’s hands close to get a good look. On most fingers the color was darker near the cuticle and got lighter toward the end of the nail. The nails on both little fingers were dark all the way to the end. He pressed on one — the tissue beneath blanched, but the nail itself was unchanged. Whatever it was, it was in the nail and not in the flesh beneath. Had he been working with heavy metals or solvents? Had he been painting? None of those, the man replied.

“I don’t know what that is,” Fishbein said finally. “You should probably see a dermatologist.” He wasn’t as worried, he told his friend, but it was weird.

It took the patient a couple of weeks to finally call his dermatologist, Dr. Melissa Burnett in Wellesley, Mass. He got an appointment right away.

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Credit…Photo illustration by Ina Jang

He saw the dermatologist in training first. She asked him about his nails and examined them, then excused herself. She found Burnett in her office and told her the man’s story. She had no idea what this could be, she blurted out. As Burnett followed her resident into the exam room, she was already putting together a list of the common causes of nail discoloration: White nails often suggested liver or kidney failure; yellow nails could be seen in fungal infections; a blackened nail could be melanoma, but it would be just the one nail.

She greeted the patient cheerfully, then took a long look at his nails. They weren’t purple but dark gray or black. And the coloring wasn’t even. It had a kind of grainy look to it. The cuticle wasn’t involved, nor was the nail fold just beyond.

One common cause of discolored nails is medications. Years ago, gold was used to treat rheumatoid arthritis. It can cause a bluish pigmentation of the skin and sometimes the nails. Had he ever been treated with gold? Never, he stated flatly. What about silver? That is sometimes added to supplements people buy off the internet. He never used supplements. There are other drugs that can do this — most common are antibiotics, especially members of the tetracycline family — but the patient wasn’t taking any of these. Heavy metals like arsenic, lead or mercury can also cause nail discoloration. But the man looked far too healthy to have an exposure to this type of toxin sufficient to cause these findings.

A Closer Look

The doctor noticed that it was only the fingers that were involved; the nails on the thumbs were normal. To the dermatologist, that, and its grainy appearance, suggested that the discoloration came from the outside rather than the inside. She picked up her dermatoscope — a kind of souped-up magnifying glass with a strong built-in light designed to evaluate pigmented lesions on the skin. Looking closely at the nail, she could see that the expanse of color was actually created by hundreds of tiny black granules on the outer surface of the nail and not within the nail itself. She asked him about his hobbies. Did he paint or work with his hands? Nope. Just Pickleball. She’d seen people with this kind of discoloration on their fingers from reading the newspaper, but never on the nails.

Suddenly she asked, “Does your wife color her hair?” She did, the man told her. “Do you ever help her?” Never. She would never let him, he said with a smile. It didn’t look as if the man dyed his hair — it was graying. She was quiet for a minute. “I have been using a new shampoo,” the man offered. He was at the drugstore and saw a shampoo that said that it could get rid of the gray and restore natural hair color. His son was getting married in the fall, and he thought it would be nice if he had his old hair color back. “But it’s not a dye,” he insisted. Besides, he added, it didn’t work.

Show me how you shampoo your hair, Burnett asked. The man began massaging his scalp, using all four fingers on each hand, but neither thumb. Certain of her diagnosis, Burnett pulled out a little packet from a drawer. When she tore it open, the man recognized the smell of acetone: nail-polish remover. The dermatologist briskly rubbed a nail, and almost instantly the gray discoloration came off, leaving the nail close to its original color.

The product he used, Just for Men Control GX Grey Reducing Shampoo, doesn’t use the word dye in its advertising or packaging. In the company’s promotional material, it says that the product “mimics the universal pigment held within a strand of hair to create every person’s natural hair color. It gradually restores pigment to gray hairs with each use.” The material suggests that this is some natural process they’ve tapped into. In fact, it’s a dye hidden inside a shampoo.

I spoke with the patient recently. He attended his son’s wedding a few days earlier, gray hair and all. I told him what I learned about how the product worked. I also told him that the package instructions suggest that men use the palms of their hands rather than their fingers to shampoo their hair “to avoid nail staining.”

He was clearly not the only man who was surprised by the product’s tendency to darken nails. On the first page of customer comments on one website, half the comments mentioned the nail discoloration. “I guess I should have read the fine print,” the patient said to me ruefully. “Next time.”

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