**Core Concept**
Morbilliform eruptions, also known as erythema multiforme or "measles-like" rash, are a type of skin manifestation characterized by a widespread, itchy, and often symmetrical rash. This condition is often associated with an underlying viral infection or drug reaction, leading to immune-mediated skin damage.

**Why the Correct Answer is Right**
The correct answer is associated with a viral infection, specifically measles, which causes a morbilliform eruption due to the direct viral cytopathic effect on the skin. The measles virus triggers an immune response, leading to the release of inflammatory cytokines and the activation of immune cells, resulting in the characteristic skin lesions. This type of rash is often seen in patients with measles or other viral infections, such as rubella and rubeola.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while Stevens-Johnson syndrome (SJS) is a severe skin condition, it is characterized by a more extensive and severe form of skin and mucous membrane involvement, often requiring hospitalization. Morbilliform eruptions are typically milder and less severe than SJS.
**Option B:** This option is incorrect because contact dermatitis is an allergic reaction to a specific substance, resulting in a localized skin reaction, whereas morbilliform eruptions are a widespread reaction to a viral infection or drug.
**Option C:** This option is incorrect because seborrheic dermatitis is a chronic skin condition characterized by a flaky, itchy rash on the scalp, face, and torso, whereas morbilliform eruptions are a more acute and widespread reaction.

**Clinical Pearl / High-Yield Fact**
Morbilliform eruptions can be a sign of an underlying viral infection or drug reaction, and a thorough medical history is essential to diagnose the underlying cause.

**Correct Answer: A. Measles**