Table 2: Differential diagnoses of bullous impetigo [9].
| Diagnosis | Distinguishing features |
| Bullous erythema multiforme | Vesicles or bullae arise from a portion of red plaques, 1 to 5 cm in diameter, on the extensor surfaces of extremities, an unusual location for impetigo |
| Bullous lupus erythematosus | Widespread vesiculobullous eruption that may be pruritic; tends to favor the upper part of the trunk and proximal upper extremities |
| Bullous pemphigoid | Vesicles and bullae appear rapidly on widespread pruritic, urticarial plaques may appear, unlike in impetigo |
| Herpes simplex virus | Grouped vesicles on an erythematous base that rupture to become erosions covered by crusts, usually on the lips and skin; may have prodromal symptoms which are not usually observed in impetigo |
| Insect bites | Bullae seen with pruritic papules grouped in areas in which bites occur |
| Pemphigus vulgaris | Non-pruritic bullae, varying in size from one to several centimeters, appear gradually and become generalized; erosions last for weeks before healing with hyperpigmentation, but no scarring occurs |
| Stevens-Johnson syndrome | Vesiculobullous disease of the skin, mouth, eyes, and genitalia; ulcerative stomatitis with hemorrhagic crusting is the most characteristic feature. Ulcerative stomatitis is not seen in impetigo |
| Thermal burns | History of burn with blistering in second-degree burns |
| Toxic epidermal necrolysis | Steven-Johnson-like mucous membrane disease followed by diffuse generalized detachment of the epidermis. Much more severe than impetigo |
| Varicella | Thin-walled vesicles on an erythematous base that start on trunk and spread to face and extremities; vesicles break and crust forms; lesions of different stages are present at the same time in a given body area as new crops develop |