anthrax (cutaneous)

Last reviewed 01/2018

Over 95% of patients present with skin involvement worldwide (1). Cutaneous anthrax, or malignant pustule (there is in fact no underlying pus unless there is secondary infection), is due to direct inoculation of the skin from infected animals or animal products

  • a single cutaneous lesion is present in majority of cases but multiple lesion may also occur
    • major features include:
      • surrounded by extensive oedema
      • painless and non tender (although may be pruritic or accompanied by a tingling sensation)
    • minor features include:
      • development of black eschar
      • three days after exposure a raised, itchy, inflamed pimple appears which progresses over 2-6 days through papular, vesicular and ulcerated stages before eschar appears
      • usually seen on exposed unprotected regions of the body, mostly on the face, neck, hands and wrists
      • discharge of serous fluid
      • local erythema and induration
      • local lymphadenopathy
      • associated with systemic malaise including headache, chills and sore throat; but afebrile (1)

It is acquired in two ways:

  • occupational:
    • 85% of cases
    • most often associated with the meat trade but also in leather workers, tanners, workers in bone meal factories and in agriculture
    • malignant pustule of the neck and shoulder was an occupational hazard of hide porters due to rubbing of infected hides on their backs
  • non-occupational:
    • occasionally affects the general public
    • formerly due to handling of infected shaving brushes, leather goods and clothes
    • now most commonly seen in amateur gardeners who use bone meal
    • has also been used as biological weapon

If the patient has at least 1 major and 2 minor features or patient has positive history of risk factors and cutaneous anthrax is strongly suspected:

  • notify Public Health Authorities:
    • immediately contact local HPU/CCDC and HPA-Colindale 24h duty doctor (020 8200 6868)
    • inform Hospital Infection Control Team
  • take initial diagnostic tests - swab from lesion for stain and culture, Blood cultures (Gloves should be worn when microbiological specimens are taken. Samples should be labelled as ‘High Risk’ and handled according to local protocols. The microbiology laboratory and reference laboratory should be notified of the suspected diagnosis and told to expect the sample)
  • start antibiotic treatment to cover B. anthracis - Ciprofloxacin orally until sensitivity testing is available (3)
    • antibiotic therapy will rapidly kill the infecting bacteria but the lesion will take weeks to fully resolve (1).

Rarely may progress to bacteraemia or meningitis without treatment (2).

Click here for example image of this condition

Reference:

Related pages:

eschar

aetiology

diagnosis

treatment

chemoprophylaxis

Bacillus anthracis

anthrax