What caused this bite?

Reader Question: Is this a bed bug bite?This is a bite on the upper arm of my 10 year old son...no clue what caused it.

Suggestion from our Editor

Most insect bites look pretty much the same. While this bite could be caused by a bed bug, one bite is usually an indication that it was caused by something else. The location of the bite on the knee is also suspect for bed bugs.

If your sons mattress is 100% clean with no markings (see mattress signs) and if there are no additional bites or signs of a live insect then you can assume that bed bugs are not the problem.