linear IgA bullous dermatosis (IgA pemphigoid)

Etiology

• pharmaceuticals
  • vancomycin most common culprit
  • captopril, amiodarone, ampicillin, amoxicillin, diclofenac, interferon-gamma, interleukin-2, iodine, lithium carbonate, penicillin G, phenytoin, piroxicam, rifampin, somatostatin, Bactrim/Septra, childhood vaccines
• idiopathic

Epidemiology

• uncommon
• 0.6 cases/100,000/year

Pathology

• subepidermal bulla
• IgA deposition in a linear pattern along the epidermal basement membrane with or without C3 & IgG deposition
• immunologically identical to chronic bullous disease of childhood
• subcorneal collection of neutrophils

* histopathology image

Clinical manifestations

• vesicles or blisters on erythematous base
• vesiculopustular eruption with clear blisters that rapidly transform into pustules
• pruritus
• clustered or discrete lesions
• distribution:
  • trunk & proximal extremities most commonly involved
  • relative sparing of mucous membranes
  • ocular involvement in some cases

* images

Laboratory

• skin biopsy: direct immunofluorescence shows deposition of intercellular IgA at epidermal surfaces
• serum IgA antibasement membrane antibodies detected by indirect immunofluorescence
  • routine serum testing generally performed with monkey esophagus as substrate
  • sensitivity increased by use of NaCl-split human skin as substrate

Differential diagnosis

• bullous pemphigoid
• dermatitis herpetiformis
• cicatricial pemphigoid
• chronic bullous disease of childhood

Management

• withdrawal of offending drug generally resolves disorder
• systemic corticosteroids
• dapsone 50-200 mg QD may be particularly useful
• sulfapyridine

More general terms

• autoimmune bullous disease (... pemphigus, bullous pemphigoid)

Additional terms

• chronic bullous disease of childhood
• IgA pemphigus