2 Year Old wakes up with red welts

My daughter woke up 2 days ago with 3 red welts on the back of her leg. I thought it was bug bites because they were much larger than just regular hives would be. I can see the "puncture"-like entry into the skin in each bite. She was miserable because they were itching so bad. We've checked her room and there is NOTHING. And this is not the first time this has occured. It's always random. That night she was wearing tight pajama pants too??

Please help.. the thought of something biting her in the night makes me feel helpless as her mother. :(

-Jamie

[Dr_Aparna]

Hi,
Hives are an itchy skin rash -- red, raised bumps with a paler center - triggered by an irritant. Common triggers include food allergies, drugs, viruses, insect bites and stings, plants, exercise, heat, and cold.

In many instances, the exact cause cannot be identified. Some children are simply more susceptible to certain irritants than others. This depends on the child's genetic predisposition.

You can give her Benadryl liquid as per the dosage schedule till the welts subside. Also apply Calamine lotion on the rash to soothe the irritated skin. Cold compresses will also help. If you can identify a cause such as an insect bite/pressure from tight clothing, then you can take measures to avoid this from recurring.
Ref:http://www.myonlinewellness.com/topic/hiveschild