Interstitial keratitis is caused by all except –
**Core Concept**
Interstitial keratitis is a rare inflammatory condition affecting the cornea, often resulting from infections, autoimmune disorders, or other systemic diseases. The condition is characterized by inflammation of the corneal stroma, leading to symptoms such as pain, photophobia, and vision loss.
**Why the Correct Answer is Right**
The correct answer is related to the etiology of interstitial keratitis. The condition is most commonly caused by infections, particularly congenital syphilis, which can lead to inflammation of the cornea. Other causes include Lyme disease, granulomatosis with polyangiitis, and autoimmune disorders such as rheumatoid arthritis. The inflammation in interstitial keratitis is a result of the body's immune response to these underlying conditions.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while syphilis is a well-known cause of interstitial keratitis, the other options listed are not directly associated with this condition.
**Option B:** This option is incorrect because while Lyme disease can cause ocular manifestations, including keratitis, it is not a primary cause of interstitial keratitis.
**Option C:** This option is incorrect because while granulomatosis with polyangiitis can cause ocular inflammation, it is not a common cause of interstitial keratitis.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that interstitial keratitis can be a manifestation of underlying systemic diseases, making a thorough medical and ocular history crucial in diagnosis and management.
**Correct Answer: D.**