I remember when my son who has SWCAH was a baby I was so confused about this. And when I asked my pediatrician and endo for advice they were not very specific. I finally figured out that there are general guidelines but every kid with CAH reacts differently to illness so you just do your best (erring on the side of caution!) until you get the hang of it. It will get easier! Now that my son is 6 I feel totally comfortable adjusting his dosage based on how sick he is acting and how high his temp is. In general, for a low fever we double the dose and for a high fever we triple it. If he is really sick, we will give him a triple dose every 6 hours. It is amazing sometimes how you can tell when the hydrocortisone is wearing off. You should give the double or triple dose at the first sign of fever or illness. Don’t worry about how long it has been since the last dose. Then double or triple at the regular medication times until your child seems to be feeling better. As long as you aren’t doing this frequently, too much hydrocortisone won’t hurt him. Kids with CAH also tend to become hypoglycemic when they have fevers so giving sugary drinks and/or popsicles is important also.

We have been really lucky and have not had to deal with a serious vomiting illness (knock on wood) so I don’t have any experience giving an injection. However, we do have the injection kit and would use if he seemed to not be responding the oral medication or if he was vomiting and couldn’t keep the medicine down.