There's also the risk of
pilonidal sinus.
When I worked in hospitals I met men who'd suffered from them to the extent of needing an operation
.
NHS page about the condition -
Pilonidal sinus
So if you often get sweaty and itch at the top of your bum-cleft, especially if you are male/hirsute/sit down a lot at work (eg as a driver) you need to get someone to look at it. If it's inflamed it could be a pilonidal sinus and will need attention.
One that's infected AND neglected can deliver a WORLD of trouble.