Bites on the skin are a poor indicator of a bed bug infestation. Bed bug bites can be misidentified, which gives the bed bugs time to spread to other areas of the house. Bed bug bites can look like bites from other insects (such as mosquitoes or spiders), rashes (such as eczema or fungal infections), or even hives. Some people do not react to bed bug bites at all.
A far more accurate way to identify a possible infestation is to look for physical signs of bed bugs. For example, spots on bedding, as described below, are one of the earliest and most accurate methods.