My 15 month old had a fever yesterday (103.6) with no other symptoms, and today is fine, except for being ultra crabby. No one else in our household is sick. The fever was brought down with tylenol, and reappeared 5 hours later and went away again with more tylenol. Other than the fever and the crabbiness, she ate really well and did not seem "sick". Today she woke up nice and cool, but was again really crabby (not like her). I gave her some motrin, thinking perhaps her teeth were bothering her. She's as happy as a clam at the moment.
Has anyone else's kids had this?
Thanks!

It's likely that there are other symptoms bothering your toddler besides the fever, she's just not old enough to verbalize them--thus, the crabbiness. If she still doesn't seem herself on Monday, it may be worth having her checked by the doctor just to be sure. But yes, there are viruses that present themselves with a high fever as the only noticeable symptom. The fever just shows that the body is trying to fight off infection.

If the high fever continues another day or so, it could be roseola - both my kids had it - ultra high fever with no other real symptoms except sometimes a rash a few days later - check her belly in a couple of days and she if she develops any kind of rash. It's nothing to worry about - just keep the fever down!