A childhood illness in a dream is read as returning to a younger stage or to an old discomfort. It points to something you thought you had outgrown resurfacing.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.