1. diaper rash infections depend on how it looks like and wat specific area its visible,and also how baby feels irritated when touched thre,,

it depnds on causes..
bacterial or fungal, your dr will be able to decide depnds on how your baby symptms are. its unlikely that its viral(only if its stomach flu),,
its mostly bacterial or fungal,,or just sometimes its normal irritation of immature infant skin,,which aggrevates further..
yes it can spread to other body parts, dependng on its nature and how its been treated with medications...

in most cases, its better to leave diaper rash open atleast until all the cream is being absorbed by the skin/area...for speedy recovery...
however, its always advisable that if situations around you are quite demanding,,keep your baby in cloth diaper with vinyl liners or keep the diaper abit loose thn you usually do,,or atleast leave it open until the application/medicine are absorbed nicely.

3. causes varies :let me list some of the normal ones..
1.could be food allergies,
2.some kids who have severe cold, cough and has viral infection,
3.could be thrush,
4. sometimes its just plain diaper rash that aggrevates and bcomes severe,,
5. secondary infections by bacteria mostly found in infants skin such as strep and staph,,or yeast/candida...
these mostly make a normal rash go abit severe.
6. sometimes its simple irritation of skin caused by dry skin..ne body part that is cleaned frequently or rubbed freq always causes irritation..and baby skin is just the right candidate !

7. in most cases, the infant diaper rash is caused because of diapers...these produce hot and humid environment which is just right for grwth of bacterria(that are mostly in stool or urine),,and it starts to irritate the skin,,sometimes its the bowel freq like loose motions/repeated,,or constipation or indigestion,,ne stomach flu infections or ne other digestive infections/viral,bacterial or fungal !
8. ne other sickness that is associated with stomach digestion,vomittng, nausea, or ne other antibiotic side effects from breastfeed mother or ne medication given to baby,,might cause a diaper rash or just an eczema.

4. the purpose of diaper is to give some rest to mothers ! esp in outside countries,,most families are nuclear,so it becomes diff for mom to keep changng the nappies or cotton cloth diaper and these disposables,give some rest. yes they absorb good bladder freqs but its expected from a mother to keep changng the dsposble diaper every 2-3hours for better hygne...
in india, the number of hands that are around a newborn to 1year are more than its in western countries,,also its not only in india, but wherever there are joint family or combined families,,kids are mostly without diapers ! for those kids if they are gettng the diaper rash the reasons are cleaning styles and hygn maintained or soap etc used for cleanng, and also other causes that i mentioned above...

yes its ok to put diaper all night,,but with rash,,use a better quality of diaper that holds a larger qty,,,,
also, always opt for a size bigger diaper,,,,if your baby is on border line wght or just 1-2lbs below the border line as mentioned diaper size,,better to upgrade your baby to bigger diaper ! it will avoid unnecesry skin irritation...because most of the times,,among sizes,,some babies graduate earlier to much more mature bladder freq(increase) compared to thr body wght and it all dpends on thr fluid intake !
keep your baby well hydrated and change your baby diaper everry 2-3hours a min before 9-10months.

5. the best remedy or treatment for ne kind of normal diaper rash,,is leave the baby without diaper and avoid ne harsh precipitating agents or ne other chemical that might irritate the skin.the skin irritants could be nothing but your perfume ! avoid all fragrances, avoid all chemicals around the baby,,and also avoid harsh detergents or fabric softners,,keep the temperature in your baby room at 75 with proper 100% cotton clothing..avoid wools etc at home,,better to make your baby wear 2-3layers of cottons and a therma or warmer in between the cottons ,,all this will ensure good skin care and will help in speedy recovery...
also, make sure your baby pants are comfortable,avoid tights or stocking that dont allow good air flow....

since it dpends more on what has caused the rashes..its hard to go for home remedy !
never use ne diaper rash ointment unless your dr sees the rash.
about all the medications that you have mentioned,,they are all for diff types of diaper rash and its better to let your dr see the rash,,and let him suggest a ointment that will give your baby speedy recovery..
avoid trying ne home remedies when it comes to skin treatments for ne child below 5years. its not advisable at all..
personal recom by someone else having same kind of diaper rash,,has to considered but not followed esp because all babies body, skin and the causes for the rashes,, are diff and if the things dont work,,it will your child who will be sufferng !! so avoid ne remedies on your own,,and consult your dr,,let him see the rash with naked eye !
at home, practice proper hygne, clean your baby well, after cleaning keep baby without diaper for a while,,let his skin come in contact with fresh air,,keep your baby room well ventilated/cross ventilation is must,,avoid too hot temp/heaters in room,,make sure to keep the temp not more than 75,,and change your baby freq not only with diapers but also with clothes..
--avoid ne use of harsh ointments or creams around baby..watever you use, use 100% natural gels, like vaseline or trusted brand of baby product..
all this should help your child remain rash free...and still if rash happens,,,check on his diet or mothers diet if bf,,,,,and if your family has history of skin irritation or ne other allergies,,its likely that your child might be prone to rashes,,

hope this helps ! pallavi replied. Thanks Hetal
I had red your answer in the original post itself (was checking it daily for ur answer, knew u were busy).

Have taken a printout and pasted in baby's room. So tht i can refer to it whenever needed! The info is so useful

Thanks again