A 4-year-old child’s eye droppings suddenly increase yellow thick may be bacterial conjunctivitis, dacryocystitis, keratitis and so on. 1. Bacterial conjunctivitis: If a 4-year-old child doesn’t pay attention to eye hygiene or often rubs his eyes with his hands, it may lead to bacterial infection, causing bacterial conjunctivitis, which may appear as a sudden increase in yellowish boogers and may be accompanied by symptoms of congestion. 2. Dacryocystitis: If a 4-year-old child has a narrowed or occluded nasolacrimal duct, it may lead to dacryocystitis, which may cause the tears to accumulate in the lacrimal sac for a long time, accompanied by bacterial infections, which may result in a sudden increase of yellowish and thick boogers in the eyes, as well as symptoms such as localized redness, swelling, warmth, pain, and so on. 3. Keratitis: When a 4-year-old child suffers from keratitis, it may be caused by bacteria, viruses, fungi and other attacks on the cornea, which can lead to an increase in secretions, the phenomenon of a sudden increase in yellowish eye droppings, accompanied by symptoms such as a foreign body sensation, photophobia, tearing and so on. When a 4-year-old child’s eye droppings suddenly increase in yellowish consistency, parents should immediately take the child to the hospital, clear the cause of the disease and then actively treat it, to avoid delaying the condition.