My dog has a rash in this genital area who knows what it is?

It is around the genitals and it looks like a rash.

It could be heat or hot spots. Possibly even a bacterial infection. Have it checked by a vet ASAP.

have it checked up it is a deadly rash

Could be a number of things, but your best option would be to take it to the Vet. Sounds to me like a dermatalogical problem, what shampoo do you wash it with??? Make sure you only use pet soap and never human soap or shampoo... You can get from most Vets and Pet Shops special shampoo for sensitive skin.. Its important to make sure when you wash the dog you dry it properly , especially around folds of skin and genital areas, so that bacteria doesnt build up.... Your dog could also have a flea allergy which can be treated with frontline etc...