My 4.5 month old is reaching for his ear. Teething or ear infection? How to tell?

Examine by a doctor. If your pediatrician finds an ear infection it is not his teeth. If there is an emerging tooth it should be obvious by looking in the mouth.
Ears. Sometimes, a 4 1/2 month old will reach for his or her ear because it just happens to be there, and not because of a teething or an ear infection. Fever, decreased appetite, lethargy, increased irritability, or decreased urine output are reasons to see the doctor for an exam.
Symptoms? Baby's can reach for their ears just to explore. Is your baby fussy? Feverish? Not feeding as well? Did s/he have a recent upper respiratory infection? If you can answer yes to any of these take your baby to the doctor.

Related Questions

5.5 month old batting at ears for 2 days. Teething or ear infection? Do I take her in?

How is the Child? Is the child happy or ill? If without fever and healthy and happy no. If the other then yes. Read more...
Hard to say. The first teeth to erupt are the lower front teeth and these typically do not cause ear pain. Babies that are teething will drool a lot and be cranky. If your baby has a fever and acts sick, or if this persists then it may be an ear infection and she needs to be checked. Read more...