Fusobacteria - Tropical ulcer
📖 About
- Tropical ulcer is a necrotising skin infection occurring in hot, humid climates.
- Fusobacterium species are almost always present, though other mixed anaerobes may contribute.
- Common in barefoot populations and in areas with poor hygiene or minor skin trauma.
🧬 Aetiology
- Initiated by minor trauma or insect bites → secondary infection with Fusobacteria and other anaerobes.
- Malnutrition and poor living conditions increase susceptibility.
- May coexist with spirochaetes or other tropical pathogens.
🩺 Clinical Features
- Intensely painful, rapidly enlarging shallow ulcer.
- Typically found on the lower limb (ankle, shin, foot).
- More common in children and young adults in tropical regions.
- If untreated → chronicity, deep tissue destruction, and risk of secondary osteomyelitis.
🔍 Differentials
- Cutaneous leishmaniasis.
- Atypical mycobacterial infection.
- Pyoderma gangrenosum.
- Venous or arterial leg ulcers.
- Yaws (Treponema pallidum pertenue).
🧪 Investigations
- Swabs and cultures from ulcer base and edges → bacterial identification.
- Biopsy if diagnosis uncertain (to exclude atypical infections or malignancy).
- Blood tests: FBC, CRP if systemic infection suspected.
💊 Management
- Antibiotics: Tetracycline and/or Metronidazole (targeting anaerobes).
- Local care: wound cleaning, dressings, and limb elevation.
- Surgical debridement to remove necrotic tissue.
- Skin grafting may be required in extensive cases.
- Nutritional support and public health interventions (footwear, hygiene) help prevention.
📚 References
🧾 Clinical Case – Tropical Ulcer (Fusobacteria)
A 19-year-old man from rural West Africa presents with a painful ulcer on his lower leg that began as a pustule two weeks earlier.
On examination, there is a deep ulcer with undermined edges and foul-smelling discharge.
He is otherwise systemically well.
Swab culture grows Fusobacterium mixed with other anaerobes.
👉 Diagnosis: Tropical ulcer due to polymicrobial infection (Fusobacteria prominent).
👉 Management: wound debridement, oral metronidazole plus broad-spectrum antibiotics, improved nutrition, and hygiene measures.
