Nizzolo travelled to the start of stage 11 in Florence but preferred to then head home rather than start the hilly 161km stage to Bagno di Romagna.
The Trek-Segafredo sprinter only started his 2017 season at the Tour of Croatia in late April after struggling with knee pain since December. He had only been training for three weeks before riding the Tour of Croatia.
He started the Giro d'Italia and wanted to show off the Italian national champion's tricolore jersey in the 100th edition but the intense racing and his allergies have made it difficult for him to continue. He finished fourth in the opening stage to Alghero and then showed a flash of his true ability by fighting to get into the front echelon on stage 3 to Cagliari. He couldn't match Fernando Gaviria's speed in the sprint but finished third.
Since then Nizzolo has struggled and finished well down the stage results. He had hoped to stay in the Giro d'Italia to contest the expected sprint finishes in Reggio Emilia and Tortona on Thursday and Friday but faced a day of suffering on the hilly stage to Bagno di Romagna.
"It was a difficult decision to quit, just as the first part of the Giro was difficult for me," Nizzolo said in Florence.
"I gave it everything to stay in the race. I've had breathing problems and the allergies certainly didn't help, so with the team we've decided to recover for a but so that I can have a good second half of the season."