Dermatological mycobacterium infecions

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2021年4月22日 (木) 09:53時点におけるVaccipedia.admin (トーク | 投稿記録)による版
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skin mycobacterial diseases

  • leprosy
    • only in human
  • cutaneous TB
    • only in human
  • non-TB mycobacterium (NTM)
    • water-borne

when to suspect

  • skin symptoms without inflammatory sings (pain, swelling, redness)
  • slow progression
  • specific patient background
    • occupation, living place, triggering event

leprosy

  • manifests in skin and peripheral nerves
  • papule, macule, plaque, hypopigmentation, nodule
  • loss of sensation, paralysis, amyotrophy
  • incubation months to >30 years

Ridley-Jopling classification

  • TT - tuberculoid
  • BT - borderline tuberculoid
  • BB - borderline borderline
  • BL - borderline lepromatous
  • LL - lepromatous
  • TT direction - abnormal or significant immune response (granulomatous) against few M. leprae bacilli
    • PB in WHO classification
    • infiltrated plaque
    • well-defined, sharp border
    • single skin lesion
    • localized, asymmetrical
    • loss of sensation at skin lesion
      • in histopathology nerves are surrounded by granuloma
  • LL direction - least cellular immunity or allergic reaction against much amount of M. leprae bacilli
    • MB in WHO classification
    • macule, papule, nodule
    • multiple skin lesion
    • widespread, symmetrical
    • loss of sensation at ...
      • in histopathology diffuse infiltrate of foamy histiocytes (macrophages) in dermis
      • Leonine facies: madarosis, saddle nose

diagnosis

  • WHO criteria: one or more cardinal signs
  1. skin lesion consistent with leprosy with definite sensory loss
  2. thickened nerve, peripheral neuropathy
  3. skin smear...

treatment

  • MB >5 lesions
  • PB 1-5 lesions

leprosy reaction

  • can develop at anytime on clinical course
    • either before or after commencement of treatment
    • even after completion of treatment
  • incidence 20-60% in multiple studies
  • Type 1 reversal reaction
    • cell-mediated delayed hypersensitivity
    • reddish, swollen, warm, painful, tender
    • systemic condition fair
  • Type 2 erythema nodosum leprosum (ENL)
    • antigen-antibody immune complex reaction
    • multiple, distributed bilaterally and symmetrically
    • with high grade fever and malaise

treatment of leprosy reaction

  • antipyretics, NSAIDs
  • steroid
  • immunosuppressant


cutaneous TB

  • estimated 1-2% of all TB patients
  • diverse range of symptoms

route of transmission

  • exogenous inoculation
    • ulcer,
    • tuberculosis verrucosa cutis, warty tuberculosis
    • orificial tuberculosis - direct contact of M.t. contained in sputum from pulmonary TB
  • endogenous spread from internal TB
    • abscess,
    • scrofuloderma - emerged from lymphadenitis
  • hematogenous
    • nodule, abscess, patch
    • as part of miliary tuberculosis
    • immunocompromised host, children
  • tuberculid - allergic reaction against M. tuberculosis
    • erythema, papule
    • in immunocompetent patient
    • skin biopsy of the eruption shows no bacteria
    • strong positivity of Mantoux test
    • Bazin erythema
      • usually localized to lower legs

treatment

  • same as of systemic tuberculosis

skin NTM

all manifest in similar skin lesions, eruptions

  • M. ulcerans = Buruli ulcer
  • M. chelonae
  • M. marinum - highest incidence
    • contact with tropical fish
  • M. avium
    • long-maintained hot bath
    • hot spring
  • M. peregrinum
  • M. massiliense (M. abscessus subsp. massiliense)