Cephalexin (Keflex) is listed as useful for which ocular infections?

• A. Conjunctival allergy
• B. Keratitis
• C. Glaucoma
• D. Dacryoadenitis, dacryocystitis, preseptal cellulitis

Answer: (D)

The main idea is choosing antibiotics based on location and likely organisms. Cephalexin is a first‑generation cephalosporin with good activity against common gram‑positive bacteria, especially Staph and Strep, which are frequent culprits in periocular and lacrimal apparatus infections. Because dacryoadenitis, dacryocystitis, and preseptal cellulitis involve superficial or periocular tissues and can respond to oral antibiotics, cephalexin is listed as useful for these conditions. Infections of the conjunctiva due to allergy aren’t bacterial infections, glaucoma isn’t treated with an antibiotic, and keratitis typically requires topical therapy focused on the cornea rather than systemic antibiotics (unless there are deeper or complicated issues). So systemic cephalexin fits the periocular infections around the eye, not the surface conjunctival allergy, corneal keratitis, or glaucoma.