Case 27: Male 22 yrs. 4 wks H/O generalized eruption with erosions and blisters on arms and legs.

• Bullous lichen planus• Lichen planus

pemphigoides• Lichenoid drug eruption• Bullous pemphigoid

IgG

Case 27: Diagnosis

• Bullous lichen planus

• Lichenoid drug eruption

• Lichen planus pemphigoides

• Bullous pemphigoid

Lichen planus pemphigoides

• Rare condition (<100 reported cases) (Kaposi 1892).

• Young adults generally affected, M>F, usually idiopathic –some drug related and paraneoplastic.

• Lichenoid eruption > blisters.

• Blisters develop on normal / erythematous skin or lichenoid areas.

• Epitope sharing: dense lichenoid inflammation > exposure of BMZ antigens> circulating autoantibodies.

• Combination of lichenoid interface dermatitis and subepidermal vesiculobullous dermatitis but variable.

• Some cases show cell poor subepidermal blisters with LP like changes at the periphery.

• Immunofluorescence profile similar to BP.

Lichen planus pemphigoides

Case 27: Differential diagnosis

• Bullous lichen planus

• Lichenoid drug eruption

• Lichen planus pemphigoides

• Bullous pemphigoid

Lichen planus pemphigoides: learning points

• Consider as a possibility when a subepidermal blisters develops in the context of a lichenoid interface dermatitis.

• Correlation with the clinical presentation and immunofluorescence profile may be needed to differentiate LPP from paraneoplastic pemphigoid.

• Prognosis and response to treatment much better than bullous pemphigoid.