Thanks for posting your query.
Yeast infection or thrush
is caused by a normal commensal fungus "Candida Albicans" present in human beings.
Human body has normal protective mechanism to prevent proliferation of candidia
albican but it gets proliferated after breech in immune system.
Thrush is also common in diabetic patients.
You should consult with gynecologist or internal medicine specialist and should go for thorough check up.
Kindly don't apply water and soap at vagina as it will remove protective mechanism and give opportunity to candida albicans.
You should apply terbinafine
ointment ate affected site.
Dr. Mayank Bhargava