A middle aged female has flaccid bullac in the skin and oral erosion. Histopathology shows intraepidermal acanthololytic blisters. The most likely diagnosis is
**Core Concept**
Pemphigus is a group of autoimmune skin diseases characterized by the formation of intraepidermal blisters due to acantholysis, which is the separation of keratinocytes from each other. This process is mediated by autoantibodies against desmoglein proteins, which are crucial components of desmosomes that hold keratinocytes together.
**Why the Correct Answer is Right**
The patient's presentation of flaccid bullae and oral erosions, along with histopathological findings of intraepidermal acanthololytic blisters, suggests an autoimmune etiology. The presence of autoantibodies against desmoglein proteins, particularly desmoglein 3, is a hallmark of pemphigus vulgaris. These autoantibodies disrupt the adhesion between keratinocytes, leading to acantholysis and blister formation. The oral erosions are a result of the autoantibodies targeting desmoglein 3, which is predominantly expressed in the oral mucosa.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because pemphigus foliaceus primarily affects the skin and is characterized by autoantibodies against desmoglein 1, which is less frequently involved in pemphigus vulgaris.
**Option B:** This option is incorrect because bullous pemphigoid is an autoimmune disease that involves autoantibodies against collagen XVII, leading to subepidermal blisters, not intraepidermal acanthololytic blisters.
**Option C:** This option is incorrect because epidermolysis bullosa is a group of genetic disorders characterized by skin fragility and blistering, but it does not involve autoantibodies against desmoglein proteins.
**Option D:** This option is incorrect because staphylococcal scalded skin syndrome (SSSS) is caused by exfoliative toxins produced by Staphylococcus aureus, leading to intraepidermal blistering, but it is not an autoimmune disease.
**Clinical Pearl / High-Yield Fact**
Pemphigus vulgaris is a classic example of an autoimmune disease that can masquerade as other conditions, such as oral thrush or lichen planus. A high index of suspicion and histopathological examination are essential for making an accurate diagnosis.
**Correct Answer:** C.