Sporotrichosis is an infection of the skin caused by a fungus that’s most often found on rose thorns, hay, sphagnum moss, twigs, and soil. The first symptom is a firm bump (nodule) on the skin that can range in color from pink to nearly purple. Over time, the nodule may become an open sore (ulcer). Untreated, the nodule and the ulcer may stay for years.
In about 60% of cases, the mold spreads along the lymph nodes. Over time, new nodules and ulcers spread in a line up the infected arm or leg. These can also last for years.
In very rare cases, the infection can spread to other parts of the body, especially if your immune system is weak. It can be difficult to treat and may be deadly.