Sporotrichosis is a chronic fungal infection typically limited to cutaneous and subcutaneous tissues. Dissemination of the infection is unusual. The causative agent is the dimorphic fungus Sporothrix schenckii. Sporotrichosis occurs worldwide but is found primarily in warm, temperate, and tropical regions. With few exceptions, the fungus gains entry into the body through trauma to the skin. In children, the infection often occurs as a solitary lesion on the face (Fig. 214.1A) or neck. Subsequent discrete nodular lesions tend to develop and spread along the lymphangitic system (Fig. 214.1B). Most cases of sporotrichosis occur in adults after intradermal inoculation of the fungus on contaminated thorns or splinters, reeds, or grasses. In many instances there is no memory of localized trauma. Floral nursery workers, gardeners, tree farmers, and others are at highest risk, although epidemic forms have been recorded in adults and children. In some endemic regions of Latin America approximately 60% of those infected are children under 15 years of age. Risk factors include playing in fields of crops and owning a cat. Cats have been associated as a risk factor by several investigators. Rare cases of disseminated sporotrichosis have been reported in patients with human immunodeficiency virus (HIV) infection. The pulmonary and extracutaneous forms are caused by inhalation of the fungus, which initially causes primary pneumonia. Secondary spread to joints, bone, muscle, and other organs is rare but may occur in the immunosuppressed host.