Britney Spears has left a Mississippi hospital with her two-year-old son Jayden James after an allergic reaction prompted the pop star to rush him to the emergency room on Sunday.

The Toxic hitmaker left the Southwest Mississippi Regional Medical Center with the tot late on Monday night, according to celebrity website TMZ.com.

The toddler apparently collapsed at the star's family home in Kentwood, Louisiana and a spokesperson for the star said on the singer's website: "Jayden James Federline was admitted to the Southwest Mississippi Regional Medical Center on Sunday, November 9th. Doctors concluded he had a reaction to something he ingested."

A source close to Spears tells People.com that Jayden suffered "a terrible allergic reaction. He had hives, was itchy and irritable."

The star and her mother Lynne spent Sunday night at the hospital with him and he "is doing fine."

Jayden James is the singer's second son with ex-husband Kevin Federline. The couple also share three-year-old Sean Preston.