is the most important reason for repeated infections like this You say that it is well controlled and you keep yourself clean...
The other possibility then, in these circumstances is some sort of Immune Deficiency
- there are several minor, uncommon, unusual conditions. You have to see a specialist in Immunology - preferably in a tertiary care teaching hospital. It needs a large battery of investigations; it is costly and there is no guarantee of successful outcome. Yet, it is worth investigating in your case.