What is not true about Erythema multiforme –
**Core Concept**
Erythema multiforme (EM) is a skin condition characterized by the sudden onset of target-like lesions, often accompanied by mucosal involvement. It is an immune-mediated response, typically triggered by infections such as herpes simplex virus (HSV), mycoplasma pneumoniae, or medications.
**Why the Correct Answer is Right**
Erythema multiforme is a type of Stevens-Johnson syndrome when mucous membranes are involved. The condition is associated with the formation of circulating autoantibodies against the epidermal growth factor receptor (EGFR) and other cellular proteins. **The condition is not primarily caused by a direct viral invasion, but rather by an immune response to the virus**.
**Why Each Wrong Option is Incorrect**
**Option A:** Erythema multiforme is associated with HSV infections. **This statement is true**.
**Option B:** Erythema multiforme is characterized by target-like lesions. **This statement is true**.
**Option C:** Erythema multiforme can be triggered by medications. **This statement is true**.
**Clinical Pearl / High-Yield Fact**
Erythema multiforme is often confused with Stevens-Johnson syndrome, which involves mucosal involvement. **The presence of mucosal lesions is a key differentiator between the two conditions**.
**Correct Answer: None. This question lacks options.