WEDNESDAY, Feb. 11 (HealthDay News) -- A wind instrument turned into the wrong instrument for a 13-year-old boy who blew his tuba so hard that he sent air into his salivary gland, where it didn't belong.

Doctors diagnosed the condition after the boy developed swelling and pain around his jaw.

"We didn't suspect such a rare problem," said Dr. Deepa Mukundan, who wrote about the case in the Feb. 12 issue of the New England Journal of Medicine. "The cure in this boy's case was to stop playing the tuba for some time."

Glassblowers and people who play brass instruments are prone to the unusual condition, known as pneumoparotid. Even kids who hold their breath can get it, said Mukundan, an assistant professor of pediatrics at the University of Toledo College of Medicine in Ohio.

Mukundan was called in to see the boy, who was suffering from pain and mild swelling on the left side of his face around the jaw. A CT scan found air in tissues below the skin, a potentially dangerous problem that could lead to infection, she said.

But the boy didn't have a fever and "looked pretty normal," Mukundan said. "That raised a flag to me that this is probably not an infection, that we have to explore other causes of air under the skin."

Doctors talked to the boy and discovered that he'd just started playing the tuba a week or two earlier. This revelation led to the diagnosis -- air in one of his salivary glands.

"Normally, the gland produces saliva and sends it to the mouth through a duct. It's like a valve and doesn't allow anything to go backwards, only forwards," Mukundan said.

But the pressure of blowing on the tuba forced air in the wrong direction, filling the gland, she said.