ARTICLE
A 64-year-old man was referred with an acute ulcer of the left foot.
His medical history was remarkable for tachyarrhythmia with atrial fibrillation,
high blood pressure treated with fluindione, digoxin and amlodipine, and
venous insufficiency most marked on his left leg. He had just spent a
two week holiday in the Dominican Republic and nothing particular had
happened there. He noticed a non inflamed edema of his left ankle during
the flight back. The day after his return an ulcer appeared on the lateral
aspect of his left foot, and enlarged rapidly.
Examination on day 8 showed a man in good general
health, with no fever. A deep exudative ulcer extending over most of the
dorsum of his foot was present, together with inflammatory edema (Fig. 1).
The border of the ulcer was raised and bluish red. Neither lymphangitis
nor enlarged lymph nodes were noted. Large varicose veins were present
on his left limb, with dermite ocre.
Tropical phagedenic
ulcer
Swabs were taken from the base and the edges of the ulcer and numerous
Fusobacterium sp. were seen in Giemsa and Gram stained smears
with numerous other bacillus and cocci, and with few inflammatory cells.
Escherichia coli, Citrobacter freundii and Enterococcus
sp., were also identified after culture of the samples. Treatment with
bed rest, clavulanic acid-amoxicillin, metronidazole was instituted. The
ulcer stopped enlarging and it began to granulate. X-rays, CT-scan, and
bone-scan were non contributory. Antibiotics were stopped after three
weeks.
Comments
Tropical phagedenic ulcer is a painful, rapidly growing, sloughing
ulcer, usually on the leg. It is mostly prevalent in hot, humid, tropical
and subtropical regions. Trauma is important in the development of the
ulcer: the trauma may be trivial, such as a scratch or an insect bite.
It most commonly occurs in under-nourished youngsters and in rural labourers,
farmers, who are vulnerable to injuries of their lower extremities. Deficiencies
in calcium, vitamins and proteins may predispose to its development. It
is thought to be a polymicrobial infection with Fusobacterium
sp. always present in the early stages, and aerobic
micro-organisms and spirochaetes playing a role [1, 2]. Considering the
rapid growth of the ulcer in our patient, the main differential diagnosis
was pyoderma gangrenosum. It spreads quickly as in our patient, but the
ulcer is commonly superficial and the edges are undermined and violaceous
in color. It does not respond to antibiotics except in some cases to minocyclin.
A venous ulcer could be considered in the differential diagnosis as the
patient had large varicose veins on this limb. But the initial site on
the dorsum of the foot and the very rapid extension were against this
diagnosis. The diagnosis of tropical phagedenic ulcer was considered most
likely in view of the bacteriological data and the rapid response to systemic
broad spectrum antibiotics. It may be that venous insufficiency predisposed
our patient to the development of this type of ulcer, which rarely occurs
in well nourished western people. Our patient was probably infected via
a trivial injury like an insect bite or a scratch which remained unnoticed.
REFERENCES
1. Adriaans B, Drasar BS. The isolation of fusobacteria from tropical
ulcers. Epidem Inf 1987; 99: 361-72.
2. Hay RJ, Adriaans BM. Bacterial Infections. In: Champion RH, Burton
JL, Burns DA, Breathnach SM, eds. Textbook of Dermatology 6th ed.
Oxford: Blackwell Science 1998: 1157-8.
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