Diagnosis is by observing the persistence of the condition, direct immunofluorescence, and detecting autoantibodies against type VII collagen. It can appear similar to porphyria cutanea tarda, pemphigoid, pemphigus, dermatitis herpetiformis, or blistering drug eruption.
Epidermolysis bullosa acquisita
Epidermolysis bullosa simplex
Ichthyosis acquisita
Ichthyosis bullosa of Siemens
Junctional epidermolysis bullosa 
Epidermolysis bullosa dystrophica
Urticaria pigmentosa
Dermatopathia pigmentosa reticularis