Answer:
The most likely diagnosis is sporotrichosis, which is caused by Sporothrix schenkii. Sporotrichosis is a granulomatous fungal infection that is transmitted through minor skin wounds in gardeners and farmers. Patients with sporotrichosis have painless chancre-like ulceration of the hand and a chain-like pattern of ulcers along the lymphatic system in the forearm.
Treatment:
1) treat with antibiotics against gram positives and an antifungal.
2) stain for fungus.
3) IV antifungal, i.e. amphotericin B.