Concomitant bullous pemphigoid and dermatitis herpetiformis

Area of Science:

• Dermatology
• Immunodermatology
• Autoimmune Blistering Diseases

Background:

• Bullous pemphigoid (BP) and dermatitis herpetiformis (DH) are distinct autoimmune blistering skin diseases.
• Both conditions are characterized by subepidermal blistering on microscopic examination.
• Co-occurrence of BP and DH is exceptionally rare in clinical practice.

Observation:

• A 77-year-old patient presented with a prolonged history of disseminated, intensely itchy papular skin lesions.
• Diagnostic investigations included direct immunofluorescence microscopy and serological autoantibody testing.
• Findings revealed characteristic immunofluorescence patterns and autoantibodies associated with both BP and DH.

Findings:

• Direct immunofluorescence showed linear IgG deposition at the basement membrane zone and granular IgA deposits in the papillary dermis.
• Circulating IgG antibodies against BP180 and BP230 (bullous pemphigoid antigens) were detected.
• IgA antibodies against endomysium, tissue transglutaminase, and gliadin (dermatitis herpetiformis-associated antigens) were identified.

Implications:

• This case highlights the importance of comprehensive diagnostic evaluation in complex autoimmune blistering diseases.
• Complete characterization of tissue-bound and serum autoantibodies is crucial for accurate diagnosis and understanding of co-occurring conditions.
• Further research into the pathogenesis of combined BP and DH may reveal shared or distinct autoimmune pathways.