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Doctor K: Draining relieves pain of black nail

DEAR DOCTOR K: I hurt my toe and now the nail has turned black. What can I do?

DEAR READER: Treatment for a subungual hematoma involves relieving pressure by draining the blood trapped under the nail. I vividly remember the first time I learned how to do it, as an intern in the emergency room. The patient was a weekend carpenter who had hammered a nail, but it wasn’t a metal nail: It was the nail on his left thumb.

My supervising physician told me to unbend a paperclip, and to heat the sharp end and push it through the man’s thumbnail to burn a hole in the nail. I replied: “What is this, the 15th century? That’s barbaric!” My supervisor smiled and told me, “You’ll remember this learning experience for a long time, and your patient will be grateful.” And I have, and he was.

I asked the patient to lie down on the exam table with his head turned to the right, and his left thumb on the table, just next to his head. Then I heated the tip of the paperclip until it was orange and said, “OK, here goes.” Then I pushed the hot paperclip through the nail and blood spurted out. The patient shouted “Hey!” and I said, “OK, it’s done.” A minute later: “Doctor, thank you. That feels so much better.”

I’ve subsequently met some mothers who tell me they’ve done this with their kids – having learned it when their mothers did it to them. But I don’t advise doing it yourself. Sometimes large hematomas that turn the whole nail black and blue can mean the toe or finger is fractured, and a tetanus shot may be needed.

Unfortunately, your nail injury is likely to be noticeable until the damaged nail grows out. For toenails, this can take about four months; fingernails usually regrow completely in about two months. If you’ve injured the base of your nail, some cosmetic changes may be permanent. But the pain will be gone, as the result of a “barbaric” but effective treatment.

Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.

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