Linear IgA Disease

Linear IgA Disease

 

Linear IgA disease is a blistering disorder of skin and mucous membranes

  • In adults, known as linear IgA bullous dermatosis
  • In children, known as chronic bullous disease of childhood

Epidemiology

  • Incidence – rare disorder
  • Gender – M:F, fairly equal distribution
  • Age of onset
    • Adult form – 30-50 year olds
    • Childhood form – birth-10 years

Risk Factors

  • Certain drugs – vancomycin, lithium, diclofenac, and others
  • Infection association
  • Autoimmune diseases – ulcerative colitis, systemic lupus erythematous, rheumatoid arthritis
  • Malignancies – lymphoma, chronic lymphocytic leukemia (rare in both)

Clinical Presentation

  • Similar to pemphigoid or epidermolysis bullosa acquisita
  • Papulovesicles, bullae or urticarial plaques on extensor, central or flexural sites with truncal involvement
  • Involvement of oral mucosal is common in adult disease, ocular involvement also occurs
  • May have severe pruritus
  • “String of pearls” lesion consisting of grouped vesicles
  • Perineal and perioral involvement common in children

Pathology and Immunopathology

  • IgA at the basement membrane zone in perilesional tissue by direct immunofluorescence; complement and lesser intense staining of IgG and IgM may also be found
    • Neutrophil involvement in linear IgA disease is usually greater than in pemphigoid and epidermolysis bullosa acquisita in which eosinophil involvement is prominent
  • Serum IgA basement membrane zone antibodies by indirect immunofluorescence binding to the epidermal, dermal or combined epidermal-dermal areas of split skin.
    • 97 kD LABD and LAD-1 are cleavage products of BP180 and are major antigenic targets
    • Type VII collagen may be antigen accounting for dermal staining on split skin

Diagnosis

  • Laboratory testing
    • Perilesional skin biopsy
      • IgA basement membrane zone antibodies positive in 80-90%
    • Serum
      • Antibodies localized to the epidermal side of split skin or showing a combined epidermal and dermal pattern
      • Dermal localization alone is rare, but does occur

Differential Diagnosis

  • Pemphigus
  • Pemphigoid
  • Epidermolysis bullosa acquisita
  • Dermatitis herpetiformis
  • Toxic epidermal necrolysis

Disease Monitoring

  • Epithelial basement membrane zone IgA antibodies

Treatment

  • Dapsone

See Also