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Podoconiosis: Nonfilarial endemic elephantiasis

Published:January 19, 2018DOI:https://doi.org/10.1016/j.ejim.2018.01.021

      Highlights

      • Podoconiosis is a cause of painless asymmetric leg swelling through exposure of bare feet to irritant alkaline clay soils.
      • The diagnosis of podoconiosis is mainly clinical.
      • Differential diagnosis include Leprotic filariasis and Lymphatic filariasis fromWucheria bancrofti
      • Treatment of podoconiosis is consistent shoe-wearing and good foot hygiene.

      1. Case presentation

      A 54-year-old male with medical history of hypertension was admitted for inability to walk and painless leg swelling. The swelling started in both feet and progressively extended to his mid legs. There was no swelling in any other parts of his body. Patient had been walking barefoot for about 10 years prior to presentation, after he became homeless. He lives under a bridge in Atlanta and walks around dirt frequently. He denied travelling outside Georgia. On examination, he had significant non pitting edema up to the knees bilaterally. The skin of his legs was wooden, hyperkeratotic, mossy and nodular, as seen in Panels A and B (Fig. 1). There was no loss of sensation and evidence of abscess. Doppler venous ultrasound did not reveal venous thrombosis.
      Fig. 1
      Fig. 1Picture of patient's legs and feet showing hyperkeratosis, nodular and mossy swelling typically seen in podoconiosis.

      2. Discussion

      The diagnosis is podoconiosis or ‘endemic non-filarial elephantiasis’, a tropical non-communicable disease caused by exposure of bare feet to irritant alkaline clay soils. It is commonly seen in barefoot agriculture workers in the highland areas of tropical Africa, Central America and north-west India [
      • Tekola Ayele F.
      • Adeyemo A.
      • Finan C.
      • et al.
      HLA class II locus and susceptibility to podoconiosis.
      ]. It is estimated that 4 million people are affected worldwide. The disease affects both women and men equally and causes lymphoedema of the lower extremities [
      • Tekola Ayele F.
      • Adeyemo A.
      • Finan C.
      • et al.
      HLA class II locus and susceptibility to podoconiosis.
      ]. Persistent contact with irritant soils and absorption of ultrafine silica particles from the soil through foot skin likely leads to progressive obliterative endolymphangitis, which triggers the typical examination findings [
      • Davey G.
      • Tekola F.
      • Newport M.J.
      Podoconiosis: non-infectious geochemical elephantiasis.
      ].
      The diagnosis of podoconiosis is mainly clinical. It must be distinguished from filarial and leprotic lymphedema, both of which could present with similar leg swelling and skin examination findings. In contrast to lymphatic filariasis from Wuchereria bancrofti, podoconiosis is ascending, usually starting in the foot and progressing to the knee but rarely involving the upper leg or the groin [
      • Korevaar D.A.
      • Visser B.J.
      Podoconiosis, a neglected tropical disease.
      ]. Furthermore, it is commonly bilateral and asymmetric. Leprotic filariasis on the other hand, is commonly associated with hand involvement and loss of sensation in affected areas. However, in vitro immunodiagnostic essay for the detection of Wucheria bancrofti antigen can be used to rapidly distinguish podoconiosis from filariasis when the diagnosis is not clear3. Our patient's history of walking barefoot, bilateral asymmetric leg swelling and skin exam findings were unequivocally consistent with podoconiosis. He received physical therapy, foot hygiene and was provided with a walker to ambulate upon discharge.
      Cases of podoconiosis in developed countries have rarely been reported. However, we believe clinicians, especially those that provide care to homeless and low income population like our patient, should be aware of its clinical presentation, pathology, diagnosis and treatment. Treatment is essentially consistent shoe-wearing and good foot hygiene.

      Conflict of interest

      The authors disclose no conflict of interest.

      References

        • Tekola Ayele F.
        • Adeyemo A.
        • Finan C.
        • et al.
        HLA class II locus and susceptibility to podoconiosis.
        N Engl J Med. 2012; 366: 1200-1208https://doi.org/10.1056/NEJMoa1108448
        • Davey G.
        • Tekola F.
        • Newport M.J.
        Podoconiosis: non-infectious geochemical elephantiasis.
        Trans R Soc Trop Med Hyg. 2007; 101: 1175-1180https://doi.org/10.1016/j.trstmh.2007.08.013
        • Korevaar D.A.
        • Visser B.J.
        Podoconiosis, a neglected tropical disease.
        Neth J Med. 2012; 70: 210-214