An elderly patient presents with itchy tense blisters on normal looking skin as well as on urticarial plaques as shown below. The most probable diagnosis is:
**Core Concept**
Pemphigus is a group of autoimmune blistering diseases characterized by the formation of tense blisters on normal-looking skin, often accompanied by urticarial plaques. This condition is caused by autoantibodies targeting desmoglein proteins, which are crucial for skin cell adhesion.
**Why the Correct Answer is Right**
The patient's presentation of itchy tense blisters on normal-looking skin, along with urticarial plaques, is highly suggestive of Pemphigus vulgaris. This condition is caused by autoantibodies targeting desmoglein 3 proteins, which are essential for skin cell adhesion. The autoantibodies bind to these proteins, disrupting the cell-cell adhesion and leading to the formation of blisters.
**Why Each Wrong Option is Incorrect**
* **Option B:** Bullous pemphigoid is a different autoimmune blistering disease characterized by the formation of tense blisters, but it typically occurs on erythematous skin, not normal-looking skin.
* **Option C:** Dermatitis herpetiformis is a skin manifestation of celiac disease, characterized by intensely itchy blisters, but it typically occurs on the elbows, knees, and buttocks, not on normal-looking skin.
**Clinical Pearl / High-Yield Fact**
Pemphigus vulgaris is often associated with other autoimmune diseases, such as lupus erythematosus and rheumatoid arthritis, and may also be triggered by certain medications, such as penicillamine and captopril.
**Correct Answer: A. Pemphigus vulgaris.**