Pseudomembranous conjunctivitis is caused by:
**Core Concept**
Pseudomembranous conjunctivitis is a type of conjunctivitis characterized by the formation of a pseudomembrane on the conjunctiva, typically caused by an infection. This condition is often associated with bacterial or viral pathogens.
**Why the Correct Answer is Right**
The correct answer is _Staphylococcus aureus_. **Staphylococcus aureus** is a common cause of pseudomembranous conjunctivitis, particularly in the presence of an allergic or irritant reaction. The bacteria produce a toxin that leads to the formation of a pseudomembrane on the conjunctiva, causing symptoms such as redness, itching, and discharge. The pathogenesis involves the adherence of bacteria to the conjunctival epithelium, followed by the release of toxins that cause inflammation and pseudomembrane formation.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because while it is a common cause of conjunctivitis, it typically causes a follicular or mucopurulent type of conjunctivitis, rather than pseudomembranous conjunctivitis.
* **Option B:** This option is incorrect because it is not typically associated with pseudomembranous conjunctivitis. Instead, it is more commonly linked to a viral or allergic cause of conjunctivitis.
* **Option D:** This option is incorrect because while it can cause conjunctivitis, it is not typically associated with pseudomembranous conjunctivitis.
**Clinical Pearl / High-Yield Fact**
Pseudomembranous conjunctivitis is often seen in the context of an allergic or irritant reaction, and may be associated with the use of contact lenses or other foreign bodies in the eye. It is essential to identify the underlying cause of the pseudomembrane, as treatment may involve addressing the underlying condition.
**Correct Answer:** C.