After crashing out of the 2018 Abu Dhabi Tour and Milan San Remo, the Manx Missile's failure to fire at the Tour and other races this season prompted further medical testing.
“This season I’ve not felt physically myself," Cavendish said in a Team Dimension Data announcement. "Despite showing good numbers on the bike I have felt that there’s been something not right.
"Given this and on the back of these medical results, I'm glad to now finally have some clarity as to why I haven't been able to perform at my optimum level during this time.
"Having received expert medical advice as a result of the findings I’ve been advised to take a period of total rest in order to fully recover. I’m now looking forward to taking the time necessary in order to get back to 100% fitness before then returning to racing again at peak physical condition."
With just two marks etched in the win column since a stellar 2016 - a season that included an Olympic silver medal on the track and four Tour de France stage victories - Cavendish received the same diagnosis in April last year.