[Anthrax: an unusual escharotic lesion]

Anthrax is basically an animal disease rarely found in humans. We report a case occurring in a young boy who had minimal signs and a suggestive skin lesion.

A 16-year-old boy living in the steppe pastures in western Algeria was hospitalized for unexplained long-duration fever. Physical examination and laboratory tests did not suggest any infectious disease among those common in our area: typhoid fever, brucellosis, meningitis. Anthrax was suggested by presence of an escarrotic black plaque measuring 2 to 3 cm localized on the left leg. The lesion was very adherent and surrounded by an inflammatory rim. The diagnosis was confirmed bacteriologically at direct examination and by culture. Pathology found epidermal necrosis without dermal inflammatory infiltration nor vascular thrombosis. Penicillin was effective in 10 days.

Bacillus anthracis, the causal agent in anthrax, is a Gram positive rod. The disease is generally seen in herbivorous animals contaminated by plant or animal products. Human anthrax is very rare but should not go unrecognized. In humans, skin contamination is the rule, causing first a vesiculopustulous lesion which progresses to an escarrotic plaque with peripheral inflammation localized on exposed areas. In our case, the hidden localization retarded diagnosis.