My 9 month old was prescribed amoxicillian for an ear infection. after three days, little red rashes are on his body. is it an allergic reaction?

Could be: Your doctor needs to look at the rash. It can be an allergic reaction to Amoxicillin but it also can be from the infection. Call your doctor for further advice.

Difficult to answer: Most commonly, the rash is associated with Amoxicillin is not a true allergy, but it is difficult to say without seeing the rash. I would recommend taking your infant to his pediatrician to be sure.