Table 4.

Differential diagnosis of vesiculobullous exanthema.

Differential Points	Vesiculobullous Exanthema	Bullous Impetigo	Varicella	Primary Immune Bullous (Take Bullous Pemphigoid, for Example)
Fever	Fever.	Generally, no fever.	Fever.	Not yet been reported.
Clinical Presentation	Blisters larger than 1cm in diameter. Widespread blistering and maculopapular eruptions. Beyond the typical palmar and plantar distribution of HFMD. Perioral, trunk and limb involvement also present.	Starts as a small blister and rapidly develops into a large blister with a loose surface. The blisters contain a clear or yellowish fluid which then becomes dark or pus-filled. The blisters rupture, resulting in a red ring of vesicles and scaly edges. Brown scab after the rupture of blisters [37].	The initial lesions often involve the scalp, face or trunk and appear as pruritic erythematous patches. Bright blisters appear on the skin, oval in shape, varying in size, surrounded by a red halo, itchy. Blisters, pustules and crusts may coexist in any one area of the skin [38].	Tense, serous or hemorrhagic bullae of 1–3 cm diameter can appear on erythematous or apparently normal skin. Urticarial or excoriated, eczematous plaques or prurigo-like lesions appear. Blisters evolve into eroded and crusted areas and then heal without scars. Symmetric distribution. Mucosal involvement is more common in the oral cavity [39].
Preferred site	Perioral, acral, and buttock predilection.	Lesions usually occur on the trunk, extremities and friction areas, such as the axillae, neck crease and nappy area. Often appear in well-defined clusters without any surrounding erythema or oedema.	A generalized rash with a concentration of skin blisters on the head, including the scalp and trunk, with fewer lesions on the extremities.	Include the lower abdomen, flexor surfaces of the limbs, groins and axillae.
Itching	Not yet been reported.	Sometimes itching and burning sensation, usually painless [40].	Usually accompanied by itching.	Almost all patients have itching.
Recurrence	Generally, no recurrence.	Generally, no recurrence.	No recurrence in general.	Not yet reported.
Duration	Lasting about two weeks.	Duration 2 to 3 weeks.	Duration 14 to 16 days.	May persist for some days to several months.
Pathogens	CVA6.	Staphylococcus aureus.	Varicella zoster virus.	The presence of circulating and tissue-bound IgG autoantibodies directed against BP180 and BP230 [41].
Prevalence age	Occurs mainly in children but also in adults.	Most often seen in infants and children, with 90% of cases occurring in children under 2 years of age [42].	Occurs mainly in children but also in adults.	Mostly occurs in the elderly population.