Which of the following is the LEAST likely indication for Doxycycline use clinically?

• A. Acne rosacea
• B. EKC
• C. Chlamydial conjunctivitis
• D. MGD

Answer: (B)

Doxycycline works in ocular conditions mainly because of its anti-inflammatory effects and its activity against certain bacteria, which makes it useful for inflammatory lid and gland diseases as well as chlamydial infections. For acne rosacea, the drug reduces facial and eyelid inflammation and is commonly used in meibomian gland dysfunction–related cases. For chlamydial conjunctivitis, it’s a systemic option that effectively targets the causative organism. For meibomian gland dysfunction, the anti-inflammatory action helps improve gland function and reduce lid margin inflammation.

Epidemic keratoconjunctivitis, on the other hand, is caused by adenovirus—a viral infection. Antibiotics like doxycycline do not treat viruses, so there’s no proven benefit from using doxycycline for EKC. Management is supportive, focusing on lubrication, hygiene, and minimizing secondary bacterial infection if it occurs.

So the least likely indication is EKC because its viral etiology means antibiotics don’t address the underlying cause.