Pemphigus diagnosis is based on the clinical aspect and the histopathological examination of the lesions and confirmed by immunofluorescence tests. Direct immunofluorescence is a key instrument for pemphigus diagnosis, but can also be used, alongside indirect immunofluorescence, as a method to monitor remissions of this condition. The direct method consists in the analysis of a tissue fragment sampled from the patient; cutaneous or mucous biopsies are currently used.

Recent sudies recommend the use of plucked hair as substrate in direct immunofluorescence in pemphigus for confirmation of diagnosis and management of the disease.