Of all known ways to buy Acanthamoeba infection, nasal irrigation was the most likely in the male case. The man had nasal polyps and was using sinus rinses to relieve his symptoms. But her symptoms didn’t start in her nasal passages — they started in her legs. Red nodules formed there and progressed to develop dark centers. Some developed into deep ulcers, while others became necrotic and turned into black crusts. Then he started to erupt on his trunk, arms and neck.
Catch the killer
Before being transferred to Yale, doctors elsewhere took multiple biopsies of his diseased skin to try to determine the mysterious cause. Tests were negative for bacterial or fungal pathogens. But they showed that his blood vessels were inflamed and filled with clumps of immune cells. Doctors were concerned that his immune system was attacking his blood vessels, causing necrotic lesions. So, they gave him immunosuppressive drugs. But his condition worsened and the wounds only progressed. When he arrived at Yale, he had a fever and a high heart rate and seemed weak. He had lost 16 pounds, was sleepy and confused. He was covered in wounds.
Yale doctors noted that the injuries began after he returned from Florida, where he spent the winter. While there, he was exposed to a red tide (caused by algae) while cleaning up after a hurricane. Otherwise, she only had a medical history of nasal polyps and asthma, which she treated with dupilumab, a monoclonal antibody drug. Given that her lesions had progressed, they performed a skin biopsy, this time finding amoeba-like cells. DNA test confirmed Acanthamoeba.
Doctors quickly put her on the five-drug regimen recommended by the Centers for Disease Control and Prevention for such infections, but she continued to get worse. They then sought and received approval from the Food and Drug Administration for a single-patient experimental trial of an antibiotic (nitroxoline) that had shown success in treating a different amoeba in another patient. After the doctors started it on the man, it worked. His fever broke for a short time, some of his injuries healed and no new ones formed.
