The histopathologic findings can vary widely as well. A tuberculoid granulomatous infiltrate is most helpful, but some patients may instead have a lymphohistiocytic infiltrate, palisading or sarcoidal granulomas, a mixed inflammatory infiltrate, or other nonspecific findings. Acid-fast bacilli staining typically produces negative results.
Treatment
Treatment of NTM skin infections is based entirely on susceptibility test results. There are no clearcut treatment guidelines. Many infections will be resistant to the more common antimicrobials, and it's quite common for resistance to emerge during the required lengthy course of treatment. How lengthy? The typical treatment duration required for a localized infection is about 4 months, climbing to 6 months for more severe or disseminated infection.
Oral clarithromycin at 500 mg twice daily is a good option to start with while awaiting the susceptibility test results, as it covers some of the more common NTM. Combination therapy is often employed to prevent or treat resistance. Surgical removal of isolated foci of infection is often helpful, according to Dr. Drage.
As for the M. chelonae infection outbreak in tattoos, once Dr. Drage and her colleagues recognized the common denominator in the cases, she decided it was time to meet the artist.
She found the tattoo artists were dismayed at the rash of complications and highly receptive to her suggestion that they switch from tap water to sterile water for their work. They're eager to learn how to have safer, better procedures, she said, but reliable information can be hard for them to come by because of the lack of professional standards.
"In the United States, people who cut hair are more regulated than people who do tattoos," Dr. Drage noted.
She reported having no relevant financial conflicts.