The cause of Adult Inclusion Conjunctivitis is which of the following?

• A. Bacterial infection transmitted sexually (STI)
• B. Viral infection
• C. Allergic conjunctivitis
• D. Fungal infection

Answer: (A)

Adult inclusion conjunctivitis is caused by Chlamydia trachomatis, a bacterium transmitted through sexual contact. This makes it a sexually acquired bacterial infection, typically presenting with mucopurulent discharge and follicular conjunctivitis, and it can be associated with genital tract infection in the partner. It is not caused by a virus, so viral conjunctivitis (often from adenovirus) is not the right cause. It is not allergic conjunctivitis, which features itching, a noninfectious discharge, and typically seasonal or associated with atopy. It is also not fungal, which is an uncommon cause and does not fit the usual presentation of adult inclusion conjunctivitis.