This blister becomes inflamed and slowly enlarges. Other areas may become infected as the fungus spreads through the lymph vessels. Nodules may form along the infected lymph channels, and the lymph glands in the armpit or elbow may become enlarged and sore. If untreated, the disease progresses slowly to the bones, abdominal organs, and uninvolved skin. But diagnosed early, the disease can be adequately treated and is rarely fatal.
Treatment is potassium iodine taken orally several times a day for up to three months.
Expect upset stomachs. I believe there is another treatment that has been developed which is preferred over this. Newer information indicates some uncertainty as to the fungal species. An advanced case I was one of the lucky people to get this disease, two years ago. The wound on the back of my hand widened and opened, and was ugly and refused to heal.