Antibiotic ear drops plus steroid ear drops
BMJ Group Medical Reference
Using antibiotic ear drops together with steroid ear drops can dry up your ear discharge. But we don't know if this treatment works better than antibiotic ear drops alone.
One example of combined drops is the antibiotic gentamicin with the steroid hydrocortisone (a brand name is Gentisone HQ).
We found two studies looking at how well this combined treatment worked, compared with antibiotic drops alone. But there were problems with the studies, which means we can't rely on the results.  
We found two other studies that looked at adults who were treated with both antibiotic ear drops and steroid ear drops for four to six weeks, compared with a dummy (placebo) treatment.   Both studies showed that the combined treatment worked better than the placebo. Between one third and one half of people taking the combined ear drops had no ear discharge after treatment, compared with one quarter of people taking the placebo.
Another study showed that the combined treatment worked better than steroid ear drops alone. 
But all of the studies were quite small, which may make them less reliable. Also, they all looked at adults.
We found one study looking at children, comparing the use of drops that included antibiotics with a steroid, and antibiotic drops alone.  In this study, the drops combined the antibiotics framycetin and gramicidin with the steroid dexamethasone. The children who were given antibiotic drops alone had drops that contained ciprofloxacin, which is a type of antibiotic known as a quinolone. The study found no real difference in effect between the combined treatment and antibiotic drops alone.
The steroids used to treat ear infections are not the anabolic steroids used by some athletes and bodybuilders. The steroids in ear drops are similar to chemicals produced naturally by our bodies to deal with inflammation.
In the studies we looked at, there was not much difference in side effects, whether or not people had steroid ear drops as well as antibiotic ear drops.