what do you do for a living? Do you wash your hands a lot?
Are they itchy?
Have you seen a dermatologist?
Well, it is unlikely that you contracted a fungus from the windows- the type of fungus that grows on windows does not usually grow on hands.
If you wash your hands a lot, you actually may be CAUSING the problem.
There is a type of eczema called dyshidrosis (aka dyshidrotic e., pompholyx, vesicular palmoplantar dermatitis, housewife's eczema) which only occurs on palms, soles, and sides of fingers and toes. Tiny opaque bumps called vesicles, thickening, and cracks are accompanied by itching which gets worse at night. A common type of hand eczema, it worsens in warm weather. It tends to occur in people who wash their hands too much- the water is irritating.
I would try washing your hands only when visibly soiled and after using the restroom and before and after eating. Apply moisturizer- like neutrogena norweigan hand creme- this is the best and I use it.
If you do not notice an improvement after 2 weeks of doing this, I would ask for a referral to a dermatologist.