Pemphigus can also be drug or neoplasia induced. Diagnosis of pemphigus is based on cytology and histopathology. Routine Histopathology Multiple biopsies should be taken from affected areas. Careful selection of lesions in early stages of development should be done. Multiple samples are required and should be placed in a special medium called Michel's transport medium.
Direct immunofluorescence is a test to detect antibodies that are deposited in the epidermis.
Unfortunately direct immunofluorescence in veterinary medicine is not often positive and thus is not a reliable way to diagnose autoimmune diseases. False positives also occur if samples are taken from footpads or noses. This method is considered superior to direct immunofluorescence for the detection of antibodies in the skin. It can be done on formalin fixed tissues allowing use of the same sample for both histopathology and immunohistochemistry studies. PV is very rare in small animals but common in people.