A 35-year-old Indian man presented to us with a chief complaint of multiple, raised, asymptomatic lesions involving the fingers of both hands for one month. The patient was apparently well a month ago when he first noticed small red raised lesions that continued to grow over days in size and number, without producing any symptoms. He resorted to some alternative medical treatment, but there was no response. On examination, there were three serosanguineous vesicles on the dorsal aspect of the right ring finger (Fig. 1), over the base (Fig. 2) of the right thumb (dorsal aspect), and over the medial aspect of the left little finger (Fig. 3), respectively. All of the vesicles had a central black eschar and a peripheral rim of hyperemia. On further enquiry, the patient revealed that he lived on a goat farm and that recently one of his goats died of continuous bleeding through all the orifices. The classical history, together with the clinical overtone, confirmed the diagnosis of malignant pustule (cutaneous anthrax). The patient was started on oral ciprofloxacin, 500 mg twice daily for a period of one month. The patient is waiting for follow-up.
Anthrax (also known as Charbon, Woolsorter's disease, and Ragpicker's disease), is an infectious disease that affects herbivorous, hoofed animals (cattle, sheep, goats, etc.) as a zoonosis. Human beings are only affected as incidental hosts. Naturally, domestic herbivores are the most important source of infection. Human disease is acquired through three routes: (i) inhalation of spores through the respiratory tract (inhalational anthrax/Woolsorter's disease; traditionally contracted in workers breathing in airborne anthrax spores while processing wool or tanning hides); (ii) ingestion of contaminated meat (gastrointestinal anthrax); and (iii) direct inoculation of spores through a cutaneous breach (contact with infected material, e.g., carcasses, hair, hide).
Presently, anthrax is rarely encountered worldwide, barring occasional outbreaks in tropical countries, parts of South America, and Europe, due to limited veterinary control of livestock and environmental conditions favoring an animal–soil–animal zoonotic cycle. Clandestine stockpiling of the bacilli and usage for mass destruction by dissident forces is also worth mentioning in this context. India, however, paints a different picture, as the large village populations, thriving on livestock and working in the tanneries, are at continuous risk. The exact incidence of human anthrax in India is lacking in literature but as yet a little less than 200 cases have been reported. Cutaneous anthrax accounts for about 95% of all human anthrax cases. Although it is endemic in many parts of India, underreporting has largely accounted for the inaccuracy in the actual incidence. Reports of occurrences in clusters or as outbreaks in endemic areas have so far been reported from south India exclusively and only once from eastern India (Midnapore district, 2000).[2, 5, 6] The causative organism, Bacillus anthracis, produces a toxin at the site of inoculation consisting of a protective antigen, edema factor, and lethal factor. This exotoxin produces vascular thrombosis, resulting in extensive tissue edema and necrosis. Thus, when skin is the portal of entry, a pruritic macule sets in initially and progresses to papulovesicle and finally, an ulcer with black, necrotic eschar, encircled by nonpitting, gelatinous, and indolent edema on the exposed surface. The following clinical features are strongly suggestive of cutaneous anthrax, if present: presence of edema, out of proportion to the size of lesion; absence of pain; and paucity of polymorphonuclear cells in Gram's stain of vesicular fluid.
Although accurate diagnosis depends upon demonstration of the thick, Gram-positive bacilli in smears from cutaneous lesions, consolidated by cultures, histopathological examination, and immunofluorescence. However, a positive culture is encountered in only 60–65% of cases, and absence of organism in smears or histopathological examination may be superfluous due to various reasons. The present patient attended in a primary healthcare setup that lacked laboratory diagnostic facilities, but some strong points helped us to make a confident diagnosis of cutaneous anthrax. They were: (i) strong history of contact with a dead animal; (ii) characteristic asymptomatic lesion over exposed areas; and (iii) absence of constitutional symptoms, suggestive of other bacterial infections.
The American Academy of Dermatology recommends that oral antibiotic therapy is sufficient for patients with cutaneous anthrax, where lesions are not located on the head or neck and there are no systemic symptoms. Ciprofloxacin or doxycycline is considered as first-line therapy, for a period of 60 days. Intravenous antibiotics (ciprofloxacin 400 mg every 12 hours or doxycycline 100 mg every 12 hours and one or two additional antibiotics to avoid resistance) have been reserved for severe cases with systemic involvement/extensive edema/lesions involving the head and neck region.
This report is purported to highlight the classical clinical picture of a relatively uncommon zoonotic disease.