A child with fever presents with multiple tender erythematous skin lesions. On microscopic examination the skin lesions are seen to have neutrophilic infiltration in the dermis. What is the diagnosis?
**Core Concept**
The question is testing the student's ability to identify a skin condition characterized by neutrophilic infiltration in the dermis, which is a specific type of inflammatory response. Neutrophilic infiltration is a hallmark of acute inflammatory reactions, particularly those involving bacterial infections.
**Why the Correct Answer is Right**
The presence of neutrophilic infiltration in the dermis suggests a condition known as **Sweet's syndrome** or **Acute Febrile Neutrophilic Dermatosis (AFND)**. This condition is characterized by the sudden onset of fever, malaise, and tender erythematous skin lesions, often accompanied by neutrophilic infiltration in the dermis. The exact cause of Sweet's syndrome is unknown, but it is thought to be related to a abnormal immune response, possibly triggered by a viral or bacterial infection.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not accurately describe a condition characterized by neutrophilic infiltration in the dermis. Although conditions like erythema multiforme can present with skin lesions, they typically involve lymphocytic infiltration, not neutrophils.
* **Option B:** This option is incorrect because it does not match the clinical presentation described in the question. Erysipelas is a type of bacterial infection that presents with a well-demarcated, tender, and erythematous skin lesion, but it typically involves lymphocytic infiltration, not neutrophils.
* **Option C:** This option is incorrect because it does not accurately describe a condition characterized by neutrophilic infiltration in the dermis. Although conditions like panniculitis can present with skin lesions, they typically involve a different type of inflammatory response.
**Clinical Pearl / High-Yield Fact**
Sweet's syndrome is a rare condition that can mimic other skin conditions, such as erythema multiforme or erysipelas. However, it is characterized by a distinctive clinical presentation, including fever, malaise, and tender erythematous skin lesions, often accompanied by neutrophilic infiltration in the dermis.
**Correct Answer:** C.