A first-grader presents with blisters and yellow crusting lesions. What is the likely diagnosis?

The presentation of blisters and yellow crusting lesions in a first-grader strongly indicates bullous impetigo as the likely diagnosis. Bullous impetigo is a bacterial skin infection commonly caused by Staphylococcus aureus that primarily affects children. It often manifests with the characteristic formation of blisters that can rupture and ooze, leading to the formation of crusts that appear golden or honey-colored.

In contrast, acute cellulitis typically presents with redness, swelling, and warmth in the affected area, without significant blistering or crust formation. Herpes zoster, also known as shingles, presents with a painful, vesicular rash in a dermatomal distribution, which is quite different from the generalized blister and crust appearance seen in this case. Erysipelas arises from streptococcal bacteria, presenting with a well-defined raised border, warmth, and redness of the skin, but does not typically involve blisters or crusts.

Therefore, the symptoms described are most aligned with bullous impetigo, making it the most appropriate diagnosis.