Sporotrichosis - Cellulitis DDx
The lesions of sporotrichosis may present in 3 different patterns.
- Lymphocutaneous or sporotrichoid pattern – 75% of cases
- Fixed cutaneous – no lymphatic dissemination; may be more likely to develop in patients previously sensitized to S schenckii
- Disseminated cutaneous – occurs with systemic involvement; rare and usually in the context of immunosuppression such as oral prednisone therapy, other immunosuppressive medications, alcohol use disorder, diabetes mellitus, hematologic malignancies, and AIDS
Thorny plants, such as barberry and rose bushes, are the most common source of cutaneous inoculation of sporotrichosis. Other plant exposures include sphagnum moss, straw, hay, soil, and mine timbers. Occupational exposures include farmers, florists, gardeners, and forestry workers. Zoonotic transmission from scratch injury or bites of infected cats, rodents, or armadillos has been reported but is a less common mode of transmission.
Untreated cutaneous sporotrichosis usually waxes and wanes over months to years without systemic manifestations.
B42.9 – Sporotrichosis, unspecified
42094007 – Sporotrichosis
- Mycobacterium marinum also causes a lymphangitic pattern on the extremity and has a similar pattern of red nodules.
- Cellulitis or erysipelas
- The typical pattern of lymphangitic spread can suggest herpes virus infections (herpes simplex and zoster).
- Cat-scratch disease
- Superficial thrombophlebitis
- Other infections such as nocardiosis, tularemia, cutaneous tuberculosis, leishmaniasis (Old World and New World), and actinomycosis may have a similar lymphangitic spread from cutaneous inoculation. Exposure and travel history are key for diagnosis.
- Sarcoidosis rarely ulcerates or spreads along lymphatics.
- Cutaneous lymphoma may have associated fevers and weight loss.
- Bacterial abscess has an acute onset.
- Pyoderma gangrenosum bleeds easily and appears vascular.
- Vasculitis does not usually have an exophytic growth pattern.
- Foreign body reaction to sea urchin spines or barnacles
- Halogenoderma (bromoderma, iododerma)