A 3-year-old child has a seizure lasting about 10 minutes with a high fever and rash. What condition should you suspect?

In this scenario, the presentation of a high fever, rash, and a seizure lasting about 10 minutes strongly suggests meningitis, particularly viral or, less commonly, bacterial meningitis. This is because the combination of high fever and seizure in a young child often points to an infectious etiology affecting the central nervous system.

In viral meningitis, the infection can cause inflammatory changes in the meninges, which may lead to fever and can irritate the brain, resulting in seizures. Additionally, the rash can be indicative of certain infections that are known to cause meningitis, such as viral exanthems or, infrequently, a serious bacterial infection leading to septic meningitis.

While other conditions such as epilepsy could lead to seizures, the acute presentation with fever and rash does not fit its typical chronic presentation. An intracranial hemorrhage could cause seizures and is a serious concern; however, it typically presents with other symptoms like altered consciousness or neurological deficits. An allergic reaction could cause a rash and potentially some systemic implications, but it would not normally lead to prolonged seizures directly related to the reaction.

Therefore, considering the clinical presentation, meningitis is the most likely condition to suspect in this case.