What condition is most likely in a child with burning and itching in the left eye, leading to bilateral involvement and nasal symptoms?

The presence of burning and itching in one eye that progresses to bilateral involvement, coupled with nasal symptoms, strongly suggests a case of viral conjunctivitis. This condition is often characterized by these symptoms due to the viral nature of the infection, which typically begins in one eye and can quickly spread to the other. The nasal symptoms indicate a potential association with a viral upper respiratory tract infection, which frequently occurs alongside conjunctivitis, especially in cases caused by adenoviruses.

In viral conjunctivitis, the accompanying symptoms often include redness and tearing, which align with the itchiness described. This condition is highly contagious and commonly spreads in environments such as schools or daycares, where children are in close contact.

Other conditions, such as herpes keratitis, corneal ulcers, and bacterial conjunctivitis, have different clinical presentations. Herpes keratitis tends to cause more severe pain and visual disturbances and is less likely to cause bilateral symptoms unless they are reactivated in both eyes. A corneal ulcer usually presents with significant pain, photophobia, and decreased vision, often not accompanied by nasal symptoms. Bacterial conjunctivitis, while also causing redness and discharge, typically features purulent discharge and may not necessarily lead to nasal symptoms in conjunction with the eye discomfort.

Thus, the