Linear dermo-epidermal IgA deposition in bullous pemphigoid

Area of Science:

• Immunodermatology
• Autoimmune blistering diseases

Background:

• Bullous pemphigoid (BP) is an autoimmune blistering disease typically characterized by IgG and C3 deposition at the basement membrane zone.
• Distinguishing BP from other IgA-mediated dermatoses can be challenging, particularly in atypical presentations.

Observation:

• A patient presented with a bullous eruption exhibiting linear IgA and C3 deposition along the basement membrane zone on direct immunofluorescence (DIF) of perilesional skin.
• Lesional clearance was observed following oral prednisone therapy.
• Prednisone treatment led to the disappearance of C3 deposition, while IgA deposition remained consistently present.

Findings:

• The findings support the hypothesis that linear in vivo IgA deposition, with or without other immunofluorescence findings, could represent a variant of bullous pemphigoid.
• The differential response of IgA and C3 deposition to prednisone therapy suggests distinct roles or origins in this specific case.

Implications:

• This case broadens the immunopathological spectrum considered within bullous pemphigoid.
• It highlights the importance of considering bullous pemphigoid in cases with linear IgA deposition, even in the absence of typical IgG findings.
• Further research is warranted to elucidate the precise mechanisms and classification of IgA-associated bullous dermatoses.