Because these are such common themes of the mind as representations of other feelings they often show up in dreams along with one another and are interpreted similarly.
The desert is a fascinating symbol because of the many different ways that this particular symbol is interpreted by the brain when it comes to dream interpretation. The desert can represent a barren wasteland in your life, but there are so many places in your life that have the potentiality to be barren like a wasteland that at this point, interpretation depends largely on yourself and your own feelings on an issue. If you have a dream in which you see a desert you are immediately going to have to think of all of the different things that are lacking in your life and what they may mean to you. Have you felt like you were in a dry spell in your love life recently? Well this might be the reason you were dreaming of a desert. Perhaps you are dreaming of a desert because you feel like you are in a cultural desert where everyone acts the same and everyone has the same opinions, you are living in an area with minimal diversity and it is really getting to you.
The desert can mean that you feel like all of the options for places to go in life around you seem fairly lackluster and like they all lead to failure. Perhaps you feel lost like you have no idea where to go in the world. This is one more reason you might be dreaming of a desert. You just have no idea where to go next and are not sure what move might be right for you next.
Dreaming of a desert island means that you feel like you need to be alone now, if only for a little while. A desert island is a place where you and anyone else can be truly isolated, alone with your own thoughts and you can think about anything you need to. This makes things a lot easier on you and a lot easier on anyone that might take mercy on you and try to help you. Sometimes the first step to getting help is admitting that you don’t want it and then seeing who is still willing to take you on.