Is It Anthrax?

Case 1:
A 34-year-old woman awoke with a painful, crusted ulcer on her upper arm. She has been repairing dry wall in her home but recalls no trauma. The necrotic ulcer features an erythematous border.

Is this anthrax?

Case 2:
Several days after a painful, progressively growing lesion erupted on his thigh, a 68-year-old man seeks medical care. He has a low-grade fever and flu-like symptoms. There is no history of trauma or bite.

Cutaneous examination reveals an erythematous plaque with a central eschar overlying a necrotic ulcer.

Anthrax or something else?

Case 1:
The sudden, overnight onset of the painful lesion led to the presumptive diagnosis of brown recluse spider bite. These arthropods prefer dark, secluded areas, such as behind walls and in attics and basements, usually in the Midwest and Southwest.

Dapsone was prescribed. Within 48 hours, the patient's pain abated, and the ulcer healed rapidly over the next 10 days without sequelae.

Case 2:
The eruption on nonexposed skin and the lesion's large size are clues that this is not anthrax. Some staphylococcal and streptococcal infections can be difficult to distinguish from early-stage anthrax.

Culture of the ulcer grew out Staphylococcus aureus, which confirmed the diagnosis of ecthyma, an ulcerative form of impetigo. This patient's infection responded slowly- but completely-to a long course of a cephalosporin.

Case 3:
A 52-year-old woman with a history of inflammatory bowel disease presents with a painful lesion on her shin of a few days' duration. She reports no trauma or bite.

The erythematous plaque with a central, dusky, cyanotic, necroticappearing bulla is draining sanguineous fluid.

Anthrax or mimic?

Case 4:
Two days earlier, a painful lesion suddenly appeared on a 49-year-old woman's thigh. The tender, erythematous papule contains a central, crusted ulcer. The patient has long-standing rheumatoid arthritis; there is no history of trauma or bite.

Anthrax or look-alike?

Case 3:
The patient's history of inflammatory bowel disease heightened the suspicion of pyoderma gangrenosum, which often occurs in persons with Crohn's disease or ulcerative colitis. Drainage from a bulla is not typical of anthrax lesions. A biopsy supported the diagnosis of pyoderma gangrenosum. Prednisone( brought about a partial response; the skin disease completely resolved following a 2-week course of ciprofloxacin(.

Case 4:
The pain and the patient's underlying connective tissue disease reduced the likelihood of anthrax. A skin biopsy confirmed the suspected diagnosis of acute vasculitis, which was caused by a flare of the patient's rheumatoid arthritis.

A complete workup ruled out more extensive internal involvement, such as kidney disease. Prednisone was added to the patient's regimen of NSAIDs; the arthritis responded to this more aggressive systemic therapy, and the vasculitis resolved.

Case 5:
A 38-year-old importer of Asian rugs is concerned about an enlarging, red "bump" on her arm. She recalls no history of trauma but frequently has superficial abrasions from handling the carpets.

The patient reports that the lesion's central blister developed during the last 2 days. The painless blister became black, and small lesions appeared near the original eruption.

Is this anthrax?

Case 6:
A 42-year-old woman presents with a 2-day history of a painful lesion on the suprapubic region. The central ulcer of the tender, erythematous plaque is draining serosanguinous fluid. She has no history of trauma or bite.

What are you looking at here?

Case 5:
The clinical appearance of this lesion-a painless, black eschar surrounded by erythema and brawny, nonpitting edema-suggested cutaneous anthrax. Satellite vesicles can also occur. One of the patient's superficial abrasions probably provided a portal for Bacillus anthracis.

The diagnosis was confirmed by Gram staining and culture of the skin lesion; these positive results obviated the need for a skin biopsy, which must be performed when the culture and Gram stain are negative for B anthracis but clinical suspicion remains high.¹

Doxycycline, 100 mg bid, or ciprofloxacin, 500 mg bid, is the recommended treatment. The recommended duration of therapy has recently been extended from 7 to 10 days to 60 days.²

Case 6: A bacterial culture grew out Staphylococcus aureus, confirming the diagnosis of folliculitis. The presentation of a painful, draining pustule or papule around a hair follicle on nonexposed skin argues against anthrax and suggests folliculitis instead. A cephalosporin is appropriate in this setting. This patient was given cephalexin, 500 mg tid, for 1 week.

Case 7:
This reddish, tender papule appeared on the arm of a 42- year-old woman 2 days after she had returned from a camping trip in Colorado. While hiking, she had sustained several tick bites. She also has a low-grade fever and mild body aches.

What does this look like to you?

Case 8:
A 58-year-old man presents with a nonproductive cough, low-grade fever, and a lesion on the dorsum of his right hand. The nontender, crusted ulcer first developed 2 or 3 days ago; now an eschar overlies the necrotic ulcer. For a few years, the patient has been taking an iron-chelating agent to treat iron overload.

Could this be anthrax?

Case 7:
The papule developed into a vesiculopustule within a few days. The lesion then evolved into a necrotic ulcer that was covered with a black eschar. The eschar was later shed, leaving a chancre-like lesion. A few days later, the patient's regional lymph nodes became tender and enlarged.

The results of Gram staining and culture of the exudate, a punch biopsy of the lesion, and serologic testing confirmed tularemia. Francisella tularensis infection usually is contracted through broken skin from direct contact with an infected animal or from the bite of an infected flea or tick. Rarely, transmission occurs through eating infected meat.

Maintain universal precautions in handling suspicious tissues or culture media; the organism is highly infectious. However, physicians are not thought to be at risk for contracting pulmonary tularemia from cutaneous lesions.

Aminoglycosides, macrolides, chloramphenicol(, and fluoroquinolones have each been used successfully to treat tularemia.

Case 8:
The initial chest film was unremarkable; however, a second film obtained 2 days later showed extensive interstitial disease. Culture of the affected hand produced Zygomycetes fungi, which subsequently grew out on blood cultures. Zygomycosis, or mucormycosis, was diagnosed. Iron chelation therapy is a risk factor for this infection.¹

Despite aggressive therapy with intravenous amphotericin B(, the patient died 3 days later.