**Core Concept**
Erythema multiformis (EM) is a skin condition characterized by the sudden onset of distinctive target lesions, often triggered by infections, medications, or other systemic factors. It is a type of hypersensitivity reaction involving the immune system, specifically T-cell activation and the release of cytokines.

**Why the Correct Answer is Right**
The correct answer is one of the statements that is not true about erythema multiformis. EM typically presents with a characteristic "target" or "bull's-eye" appearance, with concentric rings of color. It often involves the palms and soles, and can be accompanied by systemic symptoms such as fever and malaise. The pathophysiology of EM involves the activation of T-cells and the release of cytokines, such as interferon-gamma, which contribute to the inflammatory response.

**Why Each Wrong Option is Incorrect**
**Option A:**
Erythema multiformis is indeed triggered by infections, such as herpes simplex virus and mycoplasma pneumoniae. Therefore, option A is incorrect because it is a true statement.

**Option B:**
Erythema multiformis typically presents with a characteristic "target" or "bull's-eye" appearance, which is a hallmark of the condition. Therefore, option B is incorrect because it is a true statement.

**Option C:**
Erythema multiformis can be triggered by medications, such as sulfonamides and penicillins. Therefore, option C is incorrect because it is a true statement.

**Option D:**
This statement is not true about erythema multiformis. While EM can present with blistering or bullae, it is not a primary characteristic of the condition.

**Clinical Pearl / High-Yield Fact**
One important clinical correlation to remember is that erythema multiformis can be a precursor to Stevens-Johnson syndrome (SJS), a more severe skin condition characterized by widespread blistering and mucous membrane involvement.

**Correct Answer:** D.